Variables associated with run out opportunities in cricket: coaches’ perceptions versus video analyses of the Indian Premier League 2018/2019 seasons
- Authors: Sholto-Douglas, Robert
- Date: 2022-10-14
- Subjects: Indian Premier League , Cricket Coaching , Video analysis , Fielding , Run out
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365014 , vital:65670
- Description: The purpose of this investigation was to add a scientific element to the understanding of run out opportunities in T20 (twenty/twenty) formats, which would in turn, provide recommendations to players and coaches around the topic of run outs. Due to a lack of research in this field, the study was two-fold, as there is little research known on this topic. Firstly, surveying experienced coaches on what they would expect to take place during run out opportunities from different areas of the field in a T20 game. Secondly, the study looked at what happened during successful and unsuccessful run outs from different areas of the field in two Indian Premier League (IPL) seasons. The aim of the study was to determine what variables, within an area of fielding, led to a successful or non-successful run out from different zones in the field. Coaches were required to fill out a survey which asked them to give their expectations on run out opportunities during a T20 competition. The data from the questionnaire would be used to gain a greater understanding of the way coaches understand different characteristics of run outs and whether this matched the findings of the second part of this study. The second part of the study investigated run out opportunities in two consecutive IPL seasons, based on video footage, looking at how different variables impacted successful or marginally missed run out opportunities in different areas of the field and at different times of the game. The areas were put into four different zones. Zone 1 being close to the batter, zone 2 being in the inner ring, zone 3 being on the edge of the ring and zone 4 being boundary fielders. Most of the coaches believed that in zone 1 of the field, the bowler would have the most opportunities, where in fact, based on the video footage, these fell to the wicket-keeper. In zone 2 there were a larger range of fielding positions (10) that run outs fell to when analysing video footage. The coaches supported this by often naming the same fielding positions. There was a divide in zone 3. Most run out opportunities from the video footage came to extra cover, where most coaches didn’t believe that would be the case and rather mentioned mid-off and mid-on. When analysing video footage in zone 4, it had two fielding positions (long on and deep mid-wicket) make up the majority of run out chances in this area and these two positions were quoted by most of the coaches as having the most run out opportunities fall to them. Throughout the findings, as concluded from the video footage, there were some results that matched the coaches’ expectation and some results where findings from the video footage differed from the coaches’ expectations. These findings are all useful. Firstly, it validates coaching practices. Secondly, it provides coaches with greater insight as to where they aren’t getting it correct in their fielding training. In conclusion, this study found that although coaches perceptions, for the most part, matched what took place on the field, there were instances where we saw the opposite action take place. This has important practical implications for coaching and practice. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Sholto-Douglas, Robert
- Date: 2022-10-14
- Subjects: Indian Premier League , Cricket Coaching , Video analysis , Fielding , Run out
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365014 , vital:65670
- Description: The purpose of this investigation was to add a scientific element to the understanding of run out opportunities in T20 (twenty/twenty) formats, which would in turn, provide recommendations to players and coaches around the topic of run outs. Due to a lack of research in this field, the study was two-fold, as there is little research known on this topic. Firstly, surveying experienced coaches on what they would expect to take place during run out opportunities from different areas of the field in a T20 game. Secondly, the study looked at what happened during successful and unsuccessful run outs from different areas of the field in two Indian Premier League (IPL) seasons. The aim of the study was to determine what variables, within an area of fielding, led to a successful or non-successful run out from different zones in the field. Coaches were required to fill out a survey which asked them to give their expectations on run out opportunities during a T20 competition. The data from the questionnaire would be used to gain a greater understanding of the way coaches understand different characteristics of run outs and whether this matched the findings of the second part of this study. The second part of the study investigated run out opportunities in two consecutive IPL seasons, based on video footage, looking at how different variables impacted successful or marginally missed run out opportunities in different areas of the field and at different times of the game. The areas were put into four different zones. Zone 1 being close to the batter, zone 2 being in the inner ring, zone 3 being on the edge of the ring and zone 4 being boundary fielders. Most of the coaches believed that in zone 1 of the field, the bowler would have the most opportunities, where in fact, based on the video footage, these fell to the wicket-keeper. In zone 2 there were a larger range of fielding positions (10) that run outs fell to when analysing video footage. The coaches supported this by often naming the same fielding positions. There was a divide in zone 3. Most run out opportunities from the video footage came to extra cover, where most coaches didn’t believe that would be the case and rather mentioned mid-off and mid-on. When analysing video footage in zone 4, it had two fielding positions (long on and deep mid-wicket) make up the majority of run out chances in this area and these two positions were quoted by most of the coaches as having the most run out opportunities fall to them. Throughout the findings, as concluded from the video footage, there were some results that matched the coaches’ expectation and some results where findings from the video footage differed from the coaches’ expectations. These findings are all useful. Firstly, it validates coaching practices. Secondly, it provides coaches with greater insight as to where they aren’t getting it correct in their fielding training. In conclusion, this study found that although coaches perceptions, for the most part, matched what took place on the field, there were instances where we saw the opposite action take place. This has important practical implications for coaching and practice. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-10-14
Validation of an assessment tool for mental fatigue applied to rotational shift work
- Authors: Huysamen, Kirsten Christina
- Date: 2014
- Subjects: Mental fatigue , Shift systems , Performance , Motor ability , Memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5154 , http://hdl.handle.net/10962/d1013551
- Description: Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.
- Full Text:
- Date Issued: 2014
- Authors: Huysamen, Kirsten Christina
- Date: 2014
- Subjects: Mental fatigue , Shift systems , Performance , Motor ability , Memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5154 , http://hdl.handle.net/10962/d1013551
- Description: Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.
- Full Text:
- Date Issued: 2014
Time motion analyses of one-day international and twenty/20 matches and the development of a simulated batting protocol specifically designed for female cricket players
- Authors: Munro, Catherine
- Date: 2019
- Subjects: Women cricket players , Cricket -- Batting , Cricket -- Coaching , Cricket -- Physiological aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76342 , vital:30550
- Description: Background: Accurate and reliable in-game data is fundamental when designing effective batting training. A simulated batting protocol that could aid research and training has not been specifically designed for female cricketers because of a distinct lack of empirical in-game data for the women’s version of the game. Objective: The purpose of this study was to quantify the motion demands and run-breakdown of a century and T20 half-century for women’s cricket matches to establish a simulated batting protocol specifically designed for female batters. Method: Time-motion analyses of four one-day international and six T20 innings were conducted on international cricket matches played around the world between 2012 and 2017. The innings was divided into the bowling and batting innings. The ODI innings that met the criterion of 100 runs scored and T20 innings with scores above 50 runs were used in the run breakdown, which included scores from the top 10 countries ranked by the ICC. The time-motion analyses and century breakdown were utilised in the establishment of a simulated batting protocol. The simulated batting protocol for female batters was created/developed by utilising the method designed by Houghton et al., (2011), who developed the BATEX© protocol. Results: The time-motion analyses indicated that the mean duration of an ODI innings was 169 minutes. An over lasted 2.45 minutes, with 24.86 seconds between each delivery and 55 seconds between each over. When the bowling side changed to a new bowler, it was 1.12 minutes between overs. The mean score for the first power play in an ODI was 41 runs with 1.38 wickets being taken. The mean score during the second power play was 28 runs with 0.714 wickets being taken. The T20 bowling innings lasted 75.50 minutes, with an over lasting 2.52 minutes with 25.58 seconds between deliveries. The mean score in the T20 batting innings was 122 runs. During the power play, which lasted 24.35 minutes, 37 runs were scored with 1.45 wickets being taken. The simulated batting innings was then designed as four stages lasting the duration of a typical women’s century. Each stage was based on theoretical phases of play that may occur during a batting innings. Conclusion: The study indicated that the women’s game has different movement requirements compared to the men’s game in both the ODI and T20 formats. Further, the demands differ depending on the country that is playing. A training and research protocol specifically designed for female batters is an important outcome.
- Full Text:
- Date Issued: 2019
- Authors: Munro, Catherine
- Date: 2019
- Subjects: Women cricket players , Cricket -- Batting , Cricket -- Coaching , Cricket -- Physiological aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76342 , vital:30550
- Description: Background: Accurate and reliable in-game data is fundamental when designing effective batting training. A simulated batting protocol that could aid research and training has not been specifically designed for female cricketers because of a distinct lack of empirical in-game data for the women’s version of the game. Objective: The purpose of this study was to quantify the motion demands and run-breakdown of a century and T20 half-century for women’s cricket matches to establish a simulated batting protocol specifically designed for female batters. Method: Time-motion analyses of four one-day international and six T20 innings were conducted on international cricket matches played around the world between 2012 and 2017. The innings was divided into the bowling and batting innings. The ODI innings that met the criterion of 100 runs scored and T20 innings with scores above 50 runs were used in the run breakdown, which included scores from the top 10 countries ranked by the ICC. The time-motion analyses and century breakdown were utilised in the establishment of a simulated batting protocol. The simulated batting protocol for female batters was created/developed by utilising the method designed by Houghton et al., (2011), who developed the BATEX© protocol. Results: The time-motion analyses indicated that the mean duration of an ODI innings was 169 minutes. An over lasted 2.45 minutes, with 24.86 seconds between each delivery and 55 seconds between each over. When the bowling side changed to a new bowler, it was 1.12 minutes between overs. The mean score for the first power play in an ODI was 41 runs with 1.38 wickets being taken. The mean score during the second power play was 28 runs with 0.714 wickets being taken. The T20 bowling innings lasted 75.50 minutes, with an over lasting 2.52 minutes with 25.58 seconds between deliveries. The mean score in the T20 batting innings was 122 runs. During the power play, which lasted 24.35 minutes, 37 runs were scored with 1.45 wickets being taken. The simulated batting innings was then designed as four stages lasting the duration of a typical women’s century. Each stage was based on theoretical phases of play that may occur during a batting innings. Conclusion: The study indicated that the women’s game has different movement requirements compared to the men’s game in both the ODI and T20 formats. Further, the demands differ depending on the country that is playing. A training and research protocol specifically designed for female batters is an important outcome.
- Full Text:
- Date Issued: 2019
Time course of performance changes and fatigue markers during training for the ironman triathlon
- Authors: Joiner, Alexander Jason
- Date: 2010
- Subjects: Ironman triathlons -- Training , Physical education and training -- Physiological aspects , Endurance sports -- Training , Sports -- Physiological aspects , Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5133 , http://hdl.handle.net/10962/d1005212 , Ironman triathlons -- Training , Physical education and training -- Physiological aspects , Endurance sports -- Training , Sports -- Physiological aspects , Fatigue
- Description:
Suboptimal preparation for the Ironman triathlon can have detrimental effects on mental and physical condition. The purpose of this longitudinal investigation was to examine the relationship between a number of performance changes and fatigue markers during training for an Ironman as well as immediately after the event, in an attempt to better understand the effects of ultraendurance training. Eighteen athletes training for the Ironman; South Africa, 2009 were recruited for the study. Over the 6 month data collection period body mass, training load (TRIMP and Session x RPE methods), physiological responses (waking heart rate, postural dizziness, sleep ratings), changes in psychological state (profile of mood states - POMS), reported immunological responses (symptoms of illness), biochemical changes (salivary cortisol and alpha amylase) and performance (8 km submaximal running time trial (TT) and race day performance) were measured. These responses were compared to a control sample (n=15). Results show a significant increase (p<0.05) in training load (3899.4 ± 2517.8) four weeks prior to the event. Fatigue scores significantly increased (p<0.05) concurrently with this significant increase (p<0.05) in training. TT performance did not significantly (p<0.05) alter during the time course of training. It was however strongly correlated to training load (R2=0.85) and modestly related to race performance (R2=0.65). The signs and symptoms of upper respiratory tract infections (URTI) were prevalent during the training period, decreasing during the taper and race period. Large standard deviations were found within the majority of the responses. During the final two weeks of preparation, tension scores were significantly increased (p<0.05) while training load significantly decreased (p<0.05) during the final week of preparation. Cortisol increased significantly (p<0.05) immediately post race (0.507±0.15
- Full Text:
- Date Issued: 2010
- Authors: Joiner, Alexander Jason
- Date: 2010
- Subjects: Ironman triathlons -- Training , Physical education and training -- Physiological aspects , Endurance sports -- Training , Sports -- Physiological aspects , Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5133 , http://hdl.handle.net/10962/d1005212 , Ironman triathlons -- Training , Physical education and training -- Physiological aspects , Endurance sports -- Training , Sports -- Physiological aspects , Fatigue
- Description:
Suboptimal preparation for the Ironman triathlon can have detrimental effects on mental and physical condition. The purpose of this longitudinal investigation was to examine the relationship between a number of performance changes and fatigue markers during training for an Ironman as well as immediately after the event, in an attempt to better understand the effects of ultraendurance training. Eighteen athletes training for the Ironman; South Africa, 2009 were recruited for the study. Over the 6 month data collection period body mass, training load (TRIMP and Session x RPE methods), physiological responses (waking heart rate, postural dizziness, sleep ratings), changes in psychological state (profile of mood states - POMS), reported immunological responses (symptoms of illness), biochemical changes (salivary cortisol and alpha amylase) and performance (8 km submaximal running time trial (TT) and race day performance) were measured. These responses were compared to a control sample (n=15). Results show a significant increase (p<0.05) in training load (3899.4 ± 2517.8) four weeks prior to the event. Fatigue scores significantly increased (p<0.05) concurrently with this significant increase (p<0.05) in training. TT performance did not significantly (p<0.05) alter during the time course of training. It was however strongly correlated to training load (R2=0.85) and modestly related to race performance (R2=0.65). The signs and symptoms of upper respiratory tract infections (URTI) were prevalent during the training period, decreasing during the taper and race period. Large standard deviations were found within the majority of the responses. During the final two weeks of preparation, tension scores were significantly increased (p<0.05) while training load significantly decreased (p<0.05) during the final week of preparation. Cortisol increased significantly (p<0.05) immediately post race (0.507±0.15
- Full Text:
- Date Issued: 2010
Three dimensional kinetic analysis of asymmetrical lifting
- Authors: Li, Jian-Chuan
- Date: 1996
- Subjects: Lifting and carrying , Human engineering , Materials handling , Manual work
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5174 , http://hdl.handle.net/10962/d1018240
- Description: Manual lifting is dynamic in nature and involves asymmetrical loading of the human body. This study investigated kinematic and kinetic characteristics of asymmetrical lifting in three dimensions, and then constructed a 3-D biomechanical force model of the lower back which is capable of quantifying torsional stress on the human spine. Eleven healthy adult male manual workers were recruited as subjects and lifted a 1 Okg load placed at the sagittal plane (0°) and at 30°, 60° and 90° lateral planes to the right, from 150mm and 500mm initial lift heights, respectively, to an 800mm high bench in the sagittal plane. Subjects' spinal motions and the trajectorial movements of the load in three-dimensional space were monitored simultaneously by a Lumbar Motion Monitor and a V-scope Motion Analyzer. Generally, the spinal motion factors increased as a function of increasing task asymmetry and differed (p < 0.05) between the lower (150mm) and higher (500mm) levels in the sagittal plane. In all asymmetrical conditions the motion factors showed a dramatic increase at the 500mm level compared to the increase at the 150mm level. The rates of increase in the horizontal and frontal planes were greater than those in the sagittal plane. Task asymmetry had a significant effect on the spinal kinematic parameters in the frontal plane at the two lift heights, and only at the high level (500mm) in the horizontal plane, with exception of average acceleration . Initial lift height exerted a significant effect on peak velocity and acceleration in both frontal and horizontal planes and on range of motion in the horizontal plane. Kinetic characteristics of the object being lifted in three-dimensions increased with an increase in task asymmetry. The increase was more dramatic in the lateral direction in the horizontal plane. However, motion factors in the vertical direction dominated the full range of the lift, irrespective of task asymmetry and lift height. The kinetic measures differed (p < 0.05) between the lower ( 1 50mm) and the higher (500mm) levels in the vertical direction except for average force. Task asymmetry had a significant effect on dynamic measures in the anterior-posterior direction. Both task asymmetry and lift height had a significant effect on dynamic motion factors in the lateral direction. From insights gained in the empirical study a three-dimensional biomechanical force model of the lower back was constructed based on a mechanism of muscle force re-orientation in the lumbar region. Acknowledging that the lower back is designed to be able to rotate around its longitudinal axis, the proposed model accounts for compression and shear forces and a torsional moment. The model has similar predictability to Schultz and Andersson's (1981) model when the human trunk exerts only a flexion-extension moment in the sagittal plane, but additionally predicts dramatic increases in shear forces, oblique muscle forces and torsional moment under asymmetrical lifting conditions which the Schultz-Andersson model does not. The increase rates in these forces and moment are not linearly related over task asymmetric angle.
- Full Text:
- Date Issued: 1996
- Authors: Li, Jian-Chuan
- Date: 1996
- Subjects: Lifting and carrying , Human engineering , Materials handling , Manual work
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5174 , http://hdl.handle.net/10962/d1018240
- Description: Manual lifting is dynamic in nature and involves asymmetrical loading of the human body. This study investigated kinematic and kinetic characteristics of asymmetrical lifting in three dimensions, and then constructed a 3-D biomechanical force model of the lower back which is capable of quantifying torsional stress on the human spine. Eleven healthy adult male manual workers were recruited as subjects and lifted a 1 Okg load placed at the sagittal plane (0°) and at 30°, 60° and 90° lateral planes to the right, from 150mm and 500mm initial lift heights, respectively, to an 800mm high bench in the sagittal plane. Subjects' spinal motions and the trajectorial movements of the load in three-dimensional space were monitored simultaneously by a Lumbar Motion Monitor and a V-scope Motion Analyzer. Generally, the spinal motion factors increased as a function of increasing task asymmetry and differed (p < 0.05) between the lower (150mm) and higher (500mm) levels in the sagittal plane. In all asymmetrical conditions the motion factors showed a dramatic increase at the 500mm level compared to the increase at the 150mm level. The rates of increase in the horizontal and frontal planes were greater than those in the sagittal plane. Task asymmetry had a significant effect on the spinal kinematic parameters in the frontal plane at the two lift heights, and only at the high level (500mm) in the horizontal plane, with exception of average acceleration . Initial lift height exerted a significant effect on peak velocity and acceleration in both frontal and horizontal planes and on range of motion in the horizontal plane. Kinetic characteristics of the object being lifted in three-dimensions increased with an increase in task asymmetry. The increase was more dramatic in the lateral direction in the horizontal plane. However, motion factors in the vertical direction dominated the full range of the lift, irrespective of task asymmetry and lift height. The kinetic measures differed (p < 0.05) between the lower ( 1 50mm) and the higher (500mm) levels in the vertical direction except for average force. Task asymmetry had a significant effect on dynamic measures in the anterior-posterior direction. Both task asymmetry and lift height had a significant effect on dynamic motion factors in the lateral direction. From insights gained in the empirical study a three-dimensional biomechanical force model of the lower back was constructed based on a mechanism of muscle force re-orientation in the lumbar region. Acknowledging that the lower back is designed to be able to rotate around its longitudinal axis, the proposed model accounts for compression and shear forces and a torsional moment. The model has similar predictability to Schultz and Andersson's (1981) model when the human trunk exerts only a flexion-extension moment in the sagittal plane, but additionally predicts dramatic increases in shear forces, oblique muscle forces and torsional moment under asymmetrical lifting conditions which the Schultz-Andersson model does not. The increase rates in these forces and moment are not linearly related over task asymmetric angle.
- Full Text:
- Date Issued: 1996
The workload of flight attendants during short-haul flight operations: a system analysis
- Authors: Bennett, Chloe Kayla
- Date: 2020
- Subjects: Flight attendants -- Health and hygiene , Employees -- South Africa -- Workload
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123431 , vital:35437
- Description: Background and aim: Flight attendants forms a significant part in 24-hour aviation industry. Flight attendant fatigue is a significant problem in the aviation industry as it continues to jeopardize the ability to fulfil important safety and security roles which is critical in performance duty of a flight attendant. However, little attention has been accomplished to the workload, working conditions and fatigue of flight attendants crew in transport aircraft. In addition, there is currently less research that have also embraced the problematic of smaller regional/commercial operation (short-haul flight operations) inducing fatigue among short-haul flight attendants as the nature of this operation are often characterised with high productivity expectations in a demanding environment with high time pressures resulting in high workloads and fatigue. Thus, flight attendant fatigue and workload is a worldwide challenge in this operational environment and less attention has been given to the determining factors. Therefore, the aim of the study was to determine the workload factors contributing to flight attendant fatigue during short-haul flight operations. Methods (System analysis): To achieve the research aim, the work system analysis, based on the Smith and Carayon-Sainfort model was chosen as the main research approach which was conducted in two ways; based on existing literature and secondly based on expert interviews. This method provided a systemic aspect to understand the whole work system of flight attendants work during short-haul operations in order to identify all the contributing factors to flight attendant fatigue and workload. Results: The literature analysis and the data from the expert interviews highlighted significant findings to flight attendant fatigue and workload. The reasons for flight attendant fatigue operating short-haul flights can be found at organizational, task, individual, environmental levels and tools and technologies and due to the interaction of the factors. The main factors of flight attendants’ fatigue are thought primarily as a function of scheduling due to irregular, mixed schedules with early starts and late finishes, extended duty days (long working hours), as well as high workload, due to the short turnaround flights, the number of sectors flown in a single duty period and duty length and high jobs demands. In addition, flight duty and rest regulations, confined work space in the cabin, vibrations, noise and lighting, sleeping in an unfamiliar environment, family responsibilities all add to additional stress placed on the body which can influence workload and sleep and consequently influencing fatigue. Conclusion: Overall the study determined that flight attendant fatigue is a significant problem in modern industry of short-haul operations. Using this systematic approach (work system analysis based on the framework of the work system model developed by Smith and Carayon-Sainfort (1989) allowed for an accurate representation of the complexity of flight attendant work environment in short-haul aviation industries, thus contributed to an increased understanding of fatigue and risk factors that span the entire work system and aid in identifying the patterns in combination of work system variables that are associated with increased risk to flight attendant fatigue. Overall flight attendant fatigue is a product of interactions with the short-haul environment. It can have a negative impact on safety, performance and well-being. Therefore, it needs to be managed and dealt with in the near future.
- Full Text:
- Date Issued: 2020
- Authors: Bennett, Chloe Kayla
- Date: 2020
- Subjects: Flight attendants -- Health and hygiene , Employees -- South Africa -- Workload
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/123431 , vital:35437
- Description: Background and aim: Flight attendants forms a significant part in 24-hour aviation industry. Flight attendant fatigue is a significant problem in the aviation industry as it continues to jeopardize the ability to fulfil important safety and security roles which is critical in performance duty of a flight attendant. However, little attention has been accomplished to the workload, working conditions and fatigue of flight attendants crew in transport aircraft. In addition, there is currently less research that have also embraced the problematic of smaller regional/commercial operation (short-haul flight operations) inducing fatigue among short-haul flight attendants as the nature of this operation are often characterised with high productivity expectations in a demanding environment with high time pressures resulting in high workloads and fatigue. Thus, flight attendant fatigue and workload is a worldwide challenge in this operational environment and less attention has been given to the determining factors. Therefore, the aim of the study was to determine the workload factors contributing to flight attendant fatigue during short-haul flight operations. Methods (System analysis): To achieve the research aim, the work system analysis, based on the Smith and Carayon-Sainfort model was chosen as the main research approach which was conducted in two ways; based on existing literature and secondly based on expert interviews. This method provided a systemic aspect to understand the whole work system of flight attendants work during short-haul operations in order to identify all the contributing factors to flight attendant fatigue and workload. Results: The literature analysis and the data from the expert interviews highlighted significant findings to flight attendant fatigue and workload. The reasons for flight attendant fatigue operating short-haul flights can be found at organizational, task, individual, environmental levels and tools and technologies and due to the interaction of the factors. The main factors of flight attendants’ fatigue are thought primarily as a function of scheduling due to irregular, mixed schedules with early starts and late finishes, extended duty days (long working hours), as well as high workload, due to the short turnaround flights, the number of sectors flown in a single duty period and duty length and high jobs demands. In addition, flight duty and rest regulations, confined work space in the cabin, vibrations, noise and lighting, sleeping in an unfamiliar environment, family responsibilities all add to additional stress placed on the body which can influence workload and sleep and consequently influencing fatigue. Conclusion: Overall the study determined that flight attendant fatigue is a significant problem in modern industry of short-haul operations. Using this systematic approach (work system analysis based on the framework of the work system model developed by Smith and Carayon-Sainfort (1989) allowed for an accurate representation of the complexity of flight attendant work environment in short-haul aviation industries, thus contributed to an increased understanding of fatigue and risk factors that span the entire work system and aid in identifying the patterns in combination of work system variables that are associated with increased risk to flight attendant fatigue. Overall flight attendant fatigue is a product of interactions with the short-haul environment. It can have a negative impact on safety, performance and well-being. Therefore, it needs to be managed and dealt with in the near future.
- Full Text:
- Date Issued: 2020
The time course changes in selected fatigue indicators in moderately trained participants
- Authors: Maduna, Bongani Cyprian
- Date: 2019
- Subjects: Athletes -- Health and hygiene , Fatigue , Athletes -- Physiology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76354 , vital:30553
- Description: Background: During daily physical activities, individuals will encounter some level of fatigue. This is especially true for athletes who exert their bodies to achieve superior performance and attempt to delay the onset of fatigue as far as possible. However, fatigue is a progressive process that is part of physical exercise. It is therefore, important to understand the various factors associated with fatigue. Objective: The purpose of this research project was to observe the changes in perceptual, physiological responses, and workload while participants performed a fatiguing cycling exercise task. In order to observe the aforementioned changes, one of the three variables, either perceptual, physiological responses or workload was kept constant, while the other two were observed as dependent variables. There were three test conditions, which permitted each variable to be kept constant in at least one of the three test conditions. Methods: Thirty-six apparently healthy university students were recruited for the study. The exercise was of 35 minute duration for each condition, with the data collection for HR (physiological response), RPE (perceptual response), and power output (workload) occurring at two minute intervals from the eighth minute until the thirtieth minute. The participants were required to perform a peak-power-output test in order set the relative performance ranges for each participant in order to elicit an observable fatigue response from all the participants. The three conditions included constant HR response, constant workload, and constant RPE response where each participant performed all of the above conditions on separate days.Results: The perceptual (RPE) response increased significantly (p<0.05) over time in all three test conditions, even under the constant RPE condition where it was expected to remain unchanged throughout the test duration. The HR response only demonstrated a significant (p<0.05) increase over time under the constant workload condition. Lastly, workload remained constant in all three testing conditions. Conclusion: Participants may be able to exercise for longer periods during sub-maximal exercise if they disregard the RPE warning response. In the current study, the RPE response illustrated that participants were being exerted more over time; however, the participants still had physiological and workload capacity to continue exercising. This research project has confirmed the fact that fatigue is a multifaceted phenomenon. Furthermore, it has been illustrated that RPE response alone as an indicator of fatigue onset may be misleading as participants did not breach the HR and workload steady state during the current research. Therefore, it may be more appropriate to assess fatigue onset through the assessment of more than one fatigue variable in order to ensure increased accuracy of the participants’ fatigue state assessment.
- Full Text:
- Date Issued: 2019
- Authors: Maduna, Bongani Cyprian
- Date: 2019
- Subjects: Athletes -- Health and hygiene , Fatigue , Athletes -- Physiology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/76354 , vital:30553
- Description: Background: During daily physical activities, individuals will encounter some level of fatigue. This is especially true for athletes who exert their bodies to achieve superior performance and attempt to delay the onset of fatigue as far as possible. However, fatigue is a progressive process that is part of physical exercise. It is therefore, important to understand the various factors associated with fatigue. Objective: The purpose of this research project was to observe the changes in perceptual, physiological responses, and workload while participants performed a fatiguing cycling exercise task. In order to observe the aforementioned changes, one of the three variables, either perceptual, physiological responses or workload was kept constant, while the other two were observed as dependent variables. There were three test conditions, which permitted each variable to be kept constant in at least one of the three test conditions. Methods: Thirty-six apparently healthy university students were recruited for the study. The exercise was of 35 minute duration for each condition, with the data collection for HR (physiological response), RPE (perceptual response), and power output (workload) occurring at two minute intervals from the eighth minute until the thirtieth minute. The participants were required to perform a peak-power-output test in order set the relative performance ranges for each participant in order to elicit an observable fatigue response from all the participants. The three conditions included constant HR response, constant workload, and constant RPE response where each participant performed all of the above conditions on separate days.Results: The perceptual (RPE) response increased significantly (p<0.05) over time in all three test conditions, even under the constant RPE condition where it was expected to remain unchanged throughout the test duration. The HR response only demonstrated a significant (p<0.05) increase over time under the constant workload condition. Lastly, workload remained constant in all three testing conditions. Conclusion: Participants may be able to exercise for longer periods during sub-maximal exercise if they disregard the RPE warning response. In the current study, the RPE response illustrated that participants were being exerted more over time; however, the participants still had physiological and workload capacity to continue exercising. This research project has confirmed the fact that fatigue is a multifaceted phenomenon. Furthermore, it has been illustrated that RPE response alone as an indicator of fatigue onset may be misleading as participants did not breach the HR and workload steady state during the current research. Therefore, it may be more appropriate to assess fatigue onset through the assessment of more than one fatigue variable in order to ensure increased accuracy of the participants’ fatigue state assessment.
- Full Text:
- Date Issued: 2019
The physical activity status and the impact of lifestyle behaviours on workplace productivity and absenteeism of Transnet employees
- Authors: Zimmermann, Sharnae Vanessa
- Date: 2021-10
- Subjects: Transnet (Firm : South Africa) Employees , Absenteeism (Labor) South Africa Durban , Labor productivity South Africa Durban , Exercise , Sedentary behavior , Lifestyles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190077 , vital:44961
- Description: Increased sitting time, insufficient physical activity and sub-optimal body composition are all contributing to the global disease burden. This is made evident by increases in obesity, type II diabetes, cardiovascular diseases (i.e. hypertension and strokes), cancer and other non-communicable diseases resulting in absenteeism and reduced productivity in the workplace. The global rise in sitting time and physical inactivity is caused, in part, by changes in transport convenience, work roles and technological advancements. Employees working in office environments or driving trains sit for prolonged periods; something which is evident in the industry that Transnet operates in. Sitting time and physical inactivity are independent risk factors for non-communicable diseases with poor nutrition, smoking, alcohol consumption and psychological wellbeing, being separate constructs. The purpose of the study is to determine the levels of sedentary behaviour, physical inactivity, obesity, nutrition, alcohol consumption, smoking, non-communicable disease risk, mental wellbeing and their association with productivity and absenteeism in office workers and train drivers at Transnet Freight Rail, Durban. A cross-sectional study was done with 40 participants, 20 office workers and 20 train drivers. Stature (175.80 ± 9.43 ±cm) and body mass (83.85 ± 20.31 kg) were measured; and body mass index calculated (26.98 ± 5.37 kg.m2). Physical activity levels, sedentary behaviour, body mass index and other lifestyle factors were explored using an amended version of The Health and Wellbeing survey, a self-report measure. The results revealed that there was a high prevalence of sedentary behaviour (train drivers = 7.85 ± 2.21 and office workers = 8.3 ± 1.03), particularly among office workers. Most of the participants had a relatively high body mass index, placing in the overweight and obese category, particularly among train drivers. The prevalence of physical inactivity was marginally higher for office workers compared to train drivers. There were significantly (p<0.05) higher levels of physical activity within train drivers with a moderate effect size. There were limited associations found between lifestyle factors and sickness absenteeism and worker productivity. Obesity had the most prominent relationship with noncommunicable diseases, followed by high levels of sedentary behaviour, not meeting physical activity guidelines, obesity, overweight, and prolonged sitting time at work. A significant and moderate correlation was found between obesity and absenteeism (train drivers: r = 0.32 and office workers: r= 0.46), however, no associations were found between sedentary behaviour, physical activity and fruit and vegetable intake and absenteeism. Lastly, the association between physical activity and productivity among the train drivers was low negative (r=-0.15) which was not significant (p>0.05). The associations between physical activity and productivity among office workers, however, was both significant (p<0.05) and moderate positive (r=0.39). The vegetable intake among the office workers showed a significant (p<0.05) moderate positive association with productivity (r=0.49). The association between vegetable intake and productivity among the train drivers was not significant (p>0.05) and low positive (r=0.16). There was a significant (p<0.05) and moderate positive association between fruit intake and productivity among both train drivers (r=0.43) and office workers (r=0.47). No significant associations between sedentary behaviour and obesity and productivity were found. The current study provided new insight into the risks associated with lifestyle factors of office workers and train drivers in the transportation sector. The poor lifestyle factors, together with the high prevalence of sedentary behaviour and physical inactivity, provide ideal opportunities for future interventions to focus on workers productivity and overall wellbeing. The job design of train drivers and office workers does not place significant importance on employee health and wellness. Essentially they are not “healthy” but they work productively, giving reason as to why employee wellness is not a priority for employers. The current findings of the study suggest that adopting regular physical activity, healthy dietary patterns and reduced sitting time should be promoted as key components of lifestyle interventions for the prevention of non-communicable diseases in office workers and train drivers. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Zimmermann, Sharnae Vanessa
- Date: 2021-10
- Subjects: Transnet (Firm : South Africa) Employees , Absenteeism (Labor) South Africa Durban , Labor productivity South Africa Durban , Exercise , Sedentary behavior , Lifestyles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190077 , vital:44961
- Description: Increased sitting time, insufficient physical activity and sub-optimal body composition are all contributing to the global disease burden. This is made evident by increases in obesity, type II diabetes, cardiovascular diseases (i.e. hypertension and strokes), cancer and other non-communicable diseases resulting in absenteeism and reduced productivity in the workplace. The global rise in sitting time and physical inactivity is caused, in part, by changes in transport convenience, work roles and technological advancements. Employees working in office environments or driving trains sit for prolonged periods; something which is evident in the industry that Transnet operates in. Sitting time and physical inactivity are independent risk factors for non-communicable diseases with poor nutrition, smoking, alcohol consumption and psychological wellbeing, being separate constructs. The purpose of the study is to determine the levels of sedentary behaviour, physical inactivity, obesity, nutrition, alcohol consumption, smoking, non-communicable disease risk, mental wellbeing and their association with productivity and absenteeism in office workers and train drivers at Transnet Freight Rail, Durban. A cross-sectional study was done with 40 participants, 20 office workers and 20 train drivers. Stature (175.80 ± 9.43 ±cm) and body mass (83.85 ± 20.31 kg) were measured; and body mass index calculated (26.98 ± 5.37 kg.m2). Physical activity levels, sedentary behaviour, body mass index and other lifestyle factors were explored using an amended version of The Health and Wellbeing survey, a self-report measure. The results revealed that there was a high prevalence of sedentary behaviour (train drivers = 7.85 ± 2.21 and office workers = 8.3 ± 1.03), particularly among office workers. Most of the participants had a relatively high body mass index, placing in the overweight and obese category, particularly among train drivers. The prevalence of physical inactivity was marginally higher for office workers compared to train drivers. There were significantly (p<0.05) higher levels of physical activity within train drivers with a moderate effect size. There were limited associations found between lifestyle factors and sickness absenteeism and worker productivity. Obesity had the most prominent relationship with noncommunicable diseases, followed by high levels of sedentary behaviour, not meeting physical activity guidelines, obesity, overweight, and prolonged sitting time at work. A significant and moderate correlation was found between obesity and absenteeism (train drivers: r = 0.32 and office workers: r= 0.46), however, no associations were found between sedentary behaviour, physical activity and fruit and vegetable intake and absenteeism. Lastly, the association between physical activity and productivity among the train drivers was low negative (r=-0.15) which was not significant (p>0.05). The associations between physical activity and productivity among office workers, however, was both significant (p<0.05) and moderate positive (r=0.39). The vegetable intake among the office workers showed a significant (p<0.05) moderate positive association with productivity (r=0.49). The association between vegetable intake and productivity among the train drivers was not significant (p>0.05) and low positive (r=0.16). There was a significant (p<0.05) and moderate positive association between fruit intake and productivity among both train drivers (r=0.43) and office workers (r=0.47). No significant associations between sedentary behaviour and obesity and productivity were found. The current study provided new insight into the risks associated with lifestyle factors of office workers and train drivers in the transportation sector. The poor lifestyle factors, together with the high prevalence of sedentary behaviour and physical inactivity, provide ideal opportunities for future interventions to focus on workers productivity and overall wellbeing. The job design of train drivers and office workers does not place significant importance on employee health and wellness. Essentially they are not “healthy” but they work productively, giving reason as to why employee wellness is not a priority for employers. The current findings of the study suggest that adopting regular physical activity, healthy dietary patterns and reduced sitting time should be promoted as key components of lifestyle interventions for the prevention of non-communicable diseases in office workers and train drivers. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-10
The physical activity levels and preferences of South African breast cancer survivors : a pilot study
- Authors: Campbell, Belinda Claire
- Date: 2021-04
- Subjects: Breast -- Cancer , Cancer -- Patients -- South Africa , Cancer -- Patients -- Rehabilitation , Exercise -- Health aspects , Godin leisure-time activity questionnaire (GLTPAQ) , International Physical Activity Questionnaire (IPAQ)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177748 , vital:42855
- Description: Introduction: Breast cancer is currently the most commonly diagnosed cancer in South African women. Physical activity has proven to have preventative, treatment and management benefits for breast cancer and other cancers and exercise has been found as both viable and safe during cancer treatment and recovery. However, there is limited research on breast cancer and the levels and preferences of physical activity and sedentary behaviour in a South African context. Therefore, the purpose of this study was to identify levels of physical activity and sedentary behaviour of South African breast cancer survivors and to investigate the physical activity advice and participation preferences of these participants. Methods: A cross-sectional research design was implemented to identify the physical activity, sedentary behaviour levels and exercise preferences of 48 South African breast cancer survivors (age range 45 years). An online survey comprising demographic and anthropometric questions, the Godin leisure-time activity questionnaire (GLTPAQ), the International Physical Activity Questionnaire (IPAQ) and an exercise preference questionnaire was presented to participating breast cancer survivors in order to i) identify the levels of physical activity and sedentary behaviour engaged in, ii) obtain demographic and anthropometric information and iii) identify exercise preferences. A linear mixed model regression was used to examine potential associations between demographic and anthropometric variables and physical activity levels. Chi-squared and Pearson’s Product-Moment correlation tests were used to identify relationships between categorical and numerical variables. A correlation matrix was generated to further explore any correlations. Statistical significance for all measures was set at p<0.05. Results: The mean age of the group was 49 ± 9.87 years. The most common time since diagnosis was <5 years ago and the most common stage of breast cancer was stage I. The mean BMI was 27.87 ± 5.53kg/m2. The most common treatment combination was surgery with either chemotherapy or radiation. According to the leisure score index (LSI) the majority of the group (56%) was active and according to IPAQ data 60% were meeting physical activity guidelines. The highest physical activity levels were seen in the average weekly minutes of moderate-intensity activity, and there was a strong, non-significant positive correlation (p>0.05, R2 = 0.95) between moderate-intensity physical activity and total physical activity levels. High levels of weekly sedentary behaviour and sitting time (302.60 ± 169.96 minutes) were reported. A weak, non-significant, positive correlation was found between total sedentary time and BMI (p>0.05, R2 = 0.1). A weak, non-significant, negative correlation was found between age and sedentary time (p>0.05, R2 = 0.002). More participants below 50 years were insufficiently active compared to above the age of 50 years. 1.7 to 2.6 years since diagnosis saw the greatest number of insufficiently active survivors and the category over 2.6 years since diagnosis saw the most active survivors. Most breast cancer survivors (71.10% & 82.05%) indicated being interested in and feeling capable of participating in an exercise programme (p>0.05, R2 = 0.72). The favoured preference for receiving physical activity advice was face-to-face with an exercise specialist at a cancer centre before treatment. Participation preferences included starting a programme immediately after treatment, in a home-based setting with one or two other people, where walking and a moderate exercise intensity were the preferred exercise type and level of intensity. Data collection occurred both immediately prior to (42% of participants) and during (56% of participants) the South African Covid-19 lockdown, so the results should be seen in light of this context. Conclusion: The current study is one of the first to explore physical activity rates and preferences of South African breast cancer survivors. As a group and individually these survivors were meeting public physical activity guidelines and engaging in the recommended weekly minutes. The high sitting time coupled with the high overweight and obesity levels highlight the need for positive behavioural changes including improved levels of physical activity and reduced sedentary behaviour. These changes need involvement from the numerous levels of society that affect health. Broad physical activity guidelines need to be developed not only to improve physical activity levels in breast cancer survivors but to work as a preventative measure by facilitating physical activity promotion in the general population. The findings of this study demonstrate that this group of South African breast cancer survivors is open to physical activity advice, to programmes and to improving physical activity levels. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Campbell, Belinda Claire
- Date: 2021-04
- Subjects: Breast -- Cancer , Cancer -- Patients -- South Africa , Cancer -- Patients -- Rehabilitation , Exercise -- Health aspects , Godin leisure-time activity questionnaire (GLTPAQ) , International Physical Activity Questionnaire (IPAQ)
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177748 , vital:42855
- Description: Introduction: Breast cancer is currently the most commonly diagnosed cancer in South African women. Physical activity has proven to have preventative, treatment and management benefits for breast cancer and other cancers and exercise has been found as both viable and safe during cancer treatment and recovery. However, there is limited research on breast cancer and the levels and preferences of physical activity and sedentary behaviour in a South African context. Therefore, the purpose of this study was to identify levels of physical activity and sedentary behaviour of South African breast cancer survivors and to investigate the physical activity advice and participation preferences of these participants. Methods: A cross-sectional research design was implemented to identify the physical activity, sedentary behaviour levels and exercise preferences of 48 South African breast cancer survivors (age range 45 years). An online survey comprising demographic and anthropometric questions, the Godin leisure-time activity questionnaire (GLTPAQ), the International Physical Activity Questionnaire (IPAQ) and an exercise preference questionnaire was presented to participating breast cancer survivors in order to i) identify the levels of physical activity and sedentary behaviour engaged in, ii) obtain demographic and anthropometric information and iii) identify exercise preferences. A linear mixed model regression was used to examine potential associations between demographic and anthropometric variables and physical activity levels. Chi-squared and Pearson’s Product-Moment correlation tests were used to identify relationships between categorical and numerical variables. A correlation matrix was generated to further explore any correlations. Statistical significance for all measures was set at p<0.05. Results: The mean age of the group was 49 ± 9.87 years. The most common time since diagnosis was <5 years ago and the most common stage of breast cancer was stage I. The mean BMI was 27.87 ± 5.53kg/m2. The most common treatment combination was surgery with either chemotherapy or radiation. According to the leisure score index (LSI) the majority of the group (56%) was active and according to IPAQ data 60% were meeting physical activity guidelines. The highest physical activity levels were seen in the average weekly minutes of moderate-intensity activity, and there was a strong, non-significant positive correlation (p>0.05, R2 = 0.95) between moderate-intensity physical activity and total physical activity levels. High levels of weekly sedentary behaviour and sitting time (302.60 ± 169.96 minutes) were reported. A weak, non-significant, positive correlation was found between total sedentary time and BMI (p>0.05, R2 = 0.1). A weak, non-significant, negative correlation was found between age and sedentary time (p>0.05, R2 = 0.002). More participants below 50 years were insufficiently active compared to above the age of 50 years. 1.7 to 2.6 years since diagnosis saw the greatest number of insufficiently active survivors and the category over 2.6 years since diagnosis saw the most active survivors. Most breast cancer survivors (71.10% & 82.05%) indicated being interested in and feeling capable of participating in an exercise programme (p>0.05, R2 = 0.72). The favoured preference for receiving physical activity advice was face-to-face with an exercise specialist at a cancer centre before treatment. Participation preferences included starting a programme immediately after treatment, in a home-based setting with one or two other people, where walking and a moderate exercise intensity were the preferred exercise type and level of intensity. Data collection occurred both immediately prior to (42% of participants) and during (56% of participants) the South African Covid-19 lockdown, so the results should be seen in light of this context. Conclusion: The current study is one of the first to explore physical activity rates and preferences of South African breast cancer survivors. As a group and individually these survivors were meeting public physical activity guidelines and engaging in the recommended weekly minutes. The high sitting time coupled with the high overweight and obesity levels highlight the need for positive behavioural changes including improved levels of physical activity and reduced sedentary behaviour. These changes need involvement from the numerous levels of society that affect health. Broad physical activity guidelines need to be developed not only to improve physical activity levels in breast cancer survivors but to work as a preventative measure by facilitating physical activity promotion in the general population. The findings of this study demonstrate that this group of South African breast cancer survivors is open to physical activity advice, to programmes and to improving physical activity levels. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2021
- Full Text:
- Date Issued: 2021-04
The isolation of muscle activity and ground reaction force patterns associated with postural control in four load manipulation tasks
- Authors: Pettengell, Clare Louise
- Date: 2010
- Subjects: Physical fitness , Exercise , Materials handling , Manual work , Lifting and carrying
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5125 , http://hdl.handle.net/10962/d1005203 , Physical fitness , Exercise , Materials handling , Manual work , Lifting and carrying
- Description: Although much effort has been placed into the reduction of risks associated with manual materials handling, risk of musculoskeletal disorder development remains high. This may be due to the additional muscle activity necessary for the maintenance of postural equilibrium during work tasks. This research proposes that postural control and subsequent additional muscle activity is influenced by the magnitude of the external load and the degree of body movement. The objective of this research was to identify whether performing tasks with increased external load and with a greater degree of trunk motion places additional strain on the musculoskeletal system in excess of that imposed by task demands. Twenty-four male and twenty-four female subjects performed four load manipulation tasks under three loading conditions (0.8kg, 1.6kg, and 4kg). Each task comprised of a static and dynamic condition. For the static condition, subjects maintained a stipulated posture for ten seconds. The dynamic condition required subjects to move and replace a box once every three seconds, such that a complete lift and lower cycle was performed in six seconds. Throughout task completion, muscle activity of six pairs of trunk muscles were analysed using surface electromyography. This was accompanied by data regarding ground reaction forces obtained through the use of a force platform. After the completion of each condition subjects were required to identify and rate body discomfort. Differential analysis was used to isolate the muscle activity and ground reaction forces attributed to increased external load and increased trunk movement. It was found that the heaviest loading conditions (4kg) resulted in significantly greater (p<0.05) muscle activation in the majority of muscles during all tasks investigated. The trend of muscle activity attributed to load was similar in all significantly altered muscles and activation was greatest in the heaviest loading condition. A degree of movement efficiency occurred in some muscles when manipulating loads of 0.8kg and 1.6kg. At greater loads, this did not occur suggesting that heavier loading conditions result in additional strain on the body in excess of that imposed by task demands. In manipulated data, trend of vertical ground reaction forces increased with increased load in all tasks. Sagittal movement of the centre of pressure attributed to load was significantly affected in manipulated data in the second movement phase of the “hip shoulder” task and the second movement phase of the “hip twist” task. The “hip reach” task was most affected by increased load magnitude as muscle activity attributed to load was significantly different (p<0.05) under increased loading conditions in both movement phases in all muscles. Further, a significant interactional effect (p<0.05) between condition and data point was found in all muscles with the exception of the right and left lumbar erector spinae during the second movement phase of the “hip reach” task. Muscle activity associated with increased trunk motion resulted in additional strain on the trunk muscles in the “hip shoulder” and “hip reach” tasks as muscle activity associated with the static component of each of the above tasks was greater than that of the dynamic tasks. Trend of ground reaction forces attributed to increased trunk motion generally increased under increased loading conditions. Additionally, a significant interactional effect (p<0.05) between load and muscle activity pattern was found in all muscles during all tasks, with the exception of the right rectus abdominis in the first movement phase of the “hip shoulder’ task, the left rectus abdominis in the second movement phase of the “hip knee” task and the right latissimus dorsi during the first movement phase of the “hip twist” task. This was accompanied by a significant interactional effect (p<0.05) between load and sagittal centre of pressure movement attributed to load, in both movement phases of all tasks investigated. From this research it can be proposed that guidelines may underestimate risk and subsequently under predict the strain in tasks performed with greater external loads as well as tasks which require a greater degree of trunk motion. Therefore, this study illustrates the importance of the consideration of the muscle activity necessary to maintain postural equilibrium in overall load analyses.
- Full Text:
- Date Issued: 2010
- Authors: Pettengell, Clare Louise
- Date: 2010
- Subjects: Physical fitness , Exercise , Materials handling , Manual work , Lifting and carrying
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5125 , http://hdl.handle.net/10962/d1005203 , Physical fitness , Exercise , Materials handling , Manual work , Lifting and carrying
- Description: Although much effort has been placed into the reduction of risks associated with manual materials handling, risk of musculoskeletal disorder development remains high. This may be due to the additional muscle activity necessary for the maintenance of postural equilibrium during work tasks. This research proposes that postural control and subsequent additional muscle activity is influenced by the magnitude of the external load and the degree of body movement. The objective of this research was to identify whether performing tasks with increased external load and with a greater degree of trunk motion places additional strain on the musculoskeletal system in excess of that imposed by task demands. Twenty-four male and twenty-four female subjects performed four load manipulation tasks under three loading conditions (0.8kg, 1.6kg, and 4kg). Each task comprised of a static and dynamic condition. For the static condition, subjects maintained a stipulated posture for ten seconds. The dynamic condition required subjects to move and replace a box once every three seconds, such that a complete lift and lower cycle was performed in six seconds. Throughout task completion, muscle activity of six pairs of trunk muscles were analysed using surface electromyography. This was accompanied by data regarding ground reaction forces obtained through the use of a force platform. After the completion of each condition subjects were required to identify and rate body discomfort. Differential analysis was used to isolate the muscle activity and ground reaction forces attributed to increased external load and increased trunk movement. It was found that the heaviest loading conditions (4kg) resulted in significantly greater (p<0.05) muscle activation in the majority of muscles during all tasks investigated. The trend of muscle activity attributed to load was similar in all significantly altered muscles and activation was greatest in the heaviest loading condition. A degree of movement efficiency occurred in some muscles when manipulating loads of 0.8kg and 1.6kg. At greater loads, this did not occur suggesting that heavier loading conditions result in additional strain on the body in excess of that imposed by task demands. In manipulated data, trend of vertical ground reaction forces increased with increased load in all tasks. Sagittal movement of the centre of pressure attributed to load was significantly affected in manipulated data in the second movement phase of the “hip shoulder” task and the second movement phase of the “hip twist” task. The “hip reach” task was most affected by increased load magnitude as muscle activity attributed to load was significantly different (p<0.05) under increased loading conditions in both movement phases in all muscles. Further, a significant interactional effect (p<0.05) between condition and data point was found in all muscles with the exception of the right and left lumbar erector spinae during the second movement phase of the “hip reach” task. Muscle activity associated with increased trunk motion resulted in additional strain on the trunk muscles in the “hip shoulder” and “hip reach” tasks as muscle activity associated with the static component of each of the above tasks was greater than that of the dynamic tasks. Trend of ground reaction forces attributed to increased trunk motion generally increased under increased loading conditions. Additionally, a significant interactional effect (p<0.05) between load and muscle activity pattern was found in all muscles during all tasks, with the exception of the right rectus abdominis in the first movement phase of the “hip shoulder’ task, the left rectus abdominis in the second movement phase of the “hip knee” task and the right latissimus dorsi during the first movement phase of the “hip twist” task. This was accompanied by a significant interactional effect (p<0.05) between load and sagittal centre of pressure movement attributed to load, in both movement phases of all tasks investigated. From this research it can be proposed that guidelines may underestimate risk and subsequently under predict the strain in tasks performed with greater external loads as well as tasks which require a greater degree of trunk motion. Therefore, this study illustrates the importance of the consideration of the muscle activity necessary to maintain postural equilibrium in overall load analyses.
- Full Text:
- Date Issued: 2010
The influence of soccer-specific fatigue on the risk of thigh injuries in amateur black African players
- Authors: Jones, Robert Ian
- Date: 2013
- Subjects: Soccer injuries -- South Africa -- Eastern Cape Thigh -- Wounds and injuries -- South Africa -- Eastern Cape Hamstring muscle -- Wounds and injuries -- South Africa -- Eastern Cape Black people -- Wounds and injuries -- South Africa -- Eastern Cape Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5100 , http://hdl.handle.net/10962/d1001841
- Description: Background: Epidemiological findings indicate a higher risk of muscular thigh strain injury during the latter stages of both halves of soccer match-play, with muscular fatigue highlighted as a key etiological factor in injury causation. Anthropometric, biomechanical and physiological differences present in the Black African population may elicit unique thigh injury risk profiles, different from those of European and American players. Objectives: The purpose of the current research was to investigate the impact of soccer-specific fatigue on the risk of hamstring and quadricep injury in amateur Black African soccer players, in both the dominant and non-dominant legs. Methods: Participants were required to perform a soccer matchplay simulation (SAFT⁹⁰), consisting of multidirectional and utility movements, as well as frequent acceleration and deceleration. Selected physical, physiological and psychophysical responses were collected at specific time intervals throughout fatigue protocol performance. Results: Heart rate responses were observed to increase significantly (p<0.05) in response to the start of both halves, and remain elevated (but showing no further significant increase) during the performance of the remainder of the fatigue protocol. Significant (p<0.05) changes in both concentric and eccentric isokinetic variables of the knee flexors and extensors highlight the effect of muscular fatigue on performance in soccer match-play. Eccentric hamstring peak torque was observed to decrease significantly over time (60°.s⁻ₑ=17.34%, 180°.s⁻ₑ=18.27%), with significant reductions observed during both halves. The functional H:Q ratio at 180°.s⁻ₑ indicated a significant decrease over time (10.04%), with a significant decrease indicated during the second half of the SAFT⁹⁰ protocol. The passive half time interval did not result in significant changes in isokinetic variables. Isokinetic strength, work and power indicated no significant effects of leg dominance.. ‘Central’ and ‘Local’ ratings of exertion were observed to increase significantly (p<0.05) as a function of exercise duration. Conclusion: The overall reduction in both the eccentric hamstring peak torque and the functional strength ratio was illustrated to be similar to that of other soccer-specific fatigue research. As a result, the risk of thigh strain injuries is suggested to be similar regardless of playing level and race. These time dependent changes may have implications for competitive performance and increased predisposition to hamstring strain injuries during the latter stages of both halves of match-play
- Full Text:
- Date Issued: 2013
- Authors: Jones, Robert Ian
- Date: 2013
- Subjects: Soccer injuries -- South Africa -- Eastern Cape Thigh -- Wounds and injuries -- South Africa -- Eastern Cape Hamstring muscle -- Wounds and injuries -- South Africa -- Eastern Cape Black people -- Wounds and injuries -- South Africa -- Eastern Cape Fatigue
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5100 , http://hdl.handle.net/10962/d1001841
- Description: Background: Epidemiological findings indicate a higher risk of muscular thigh strain injury during the latter stages of both halves of soccer match-play, with muscular fatigue highlighted as a key etiological factor in injury causation. Anthropometric, biomechanical and physiological differences present in the Black African population may elicit unique thigh injury risk profiles, different from those of European and American players. Objectives: The purpose of the current research was to investigate the impact of soccer-specific fatigue on the risk of hamstring and quadricep injury in amateur Black African soccer players, in both the dominant and non-dominant legs. Methods: Participants were required to perform a soccer matchplay simulation (SAFT⁹⁰), consisting of multidirectional and utility movements, as well as frequent acceleration and deceleration. Selected physical, physiological and psychophysical responses were collected at specific time intervals throughout fatigue protocol performance. Results: Heart rate responses were observed to increase significantly (p<0.05) in response to the start of both halves, and remain elevated (but showing no further significant increase) during the performance of the remainder of the fatigue protocol. Significant (p<0.05) changes in both concentric and eccentric isokinetic variables of the knee flexors and extensors highlight the effect of muscular fatigue on performance in soccer match-play. Eccentric hamstring peak torque was observed to decrease significantly over time (60°.s⁻ₑ=17.34%, 180°.s⁻ₑ=18.27%), with significant reductions observed during both halves. The functional H:Q ratio at 180°.s⁻ₑ indicated a significant decrease over time (10.04%), with a significant decrease indicated during the second half of the SAFT⁹⁰ protocol. The passive half time interval did not result in significant changes in isokinetic variables. Isokinetic strength, work and power indicated no significant effects of leg dominance.. ‘Central’ and ‘Local’ ratings of exertion were observed to increase significantly (p<0.05) as a function of exercise duration. Conclusion: The overall reduction in both the eccentric hamstring peak torque and the functional strength ratio was illustrated to be similar to that of other soccer-specific fatigue research. As a result, the risk of thigh strain injuries is suggested to be similar regardless of playing level and race. These time dependent changes may have implications for competitive performance and increased predisposition to hamstring strain injuries during the latter stages of both halves of match-play
- Full Text:
- Date Issued: 2013
The incidence of musculoskeletal disorders and stakeholder perceptions of work challenges in South-Eastern Nigerian quarry mining industry
- Authors: Egwuonwu, Victor Afamerfuna
- Date: 2020
- Subjects: Quarries and quarrying -- Health aspects -- Nigeria , Musculoskeletal system -- Diseases -- Nigeria , Miners -- Health and hygiene -- Nigeria
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/141263 , vital:37957
- Description: Musculoskeletal disorders (MSDs) are very common among industrial labourers, leading to sick leave absence, disability and low productivity at work. MSDs have multifactorial causes, thereby making it difficult to pinpoint the extent of the contributions of the various risks regarding the mechanism of its pathophysiology. Previously, attempts were made to study regional pain symptoms in varying occupational groups, disregarding the particularities of the different workplace situations. It is important to highlight, that quantifying physical exposure factors that contribute to MSDs occurrence using quantitative approach alone could be inadequate. It is therefore imperative to incorporate qualitative approach to unmask accompanying psychosocial stressors, which are mostly explanatory variables. The study investigated the following: 12-month retrospective prevalence of MSDs, prospective incidence, risk factors and pattern of MSDs in a 6-month follow-up survey of selected quarry mineworkers, who reported MSDs complaints at the mine clinic. The study also determined the level of psychosocial stress associated with working in the mine by understanding stakeholders’ perception of work challenges, and how it influenced recurrence of MSDs. The study utilised a mixed method design with two phases: phase 1 was an initial baseline retrospective prevalence and a prospective cohort-control incidence survey. The Cultural and Psychosocial Influence on Disability (CUPID) questionnaire was translated into an Igbo-language version, cross-culturally adapted and utilized. The instrument was administered via oral interview and sought information on the following: demographic characteristics; pain in different anatomical sites and associated disability for tasks of daily living; as well as information on any change of job and reason during the study period, recent pain in different anatomical sites and associated disability for tasks of daily living; distress from common somatic symptoms; mental health status, sickness absence in the past 5-months for musculoskeletal pain. Phase 2 was a qualitative focus group discussion that engaged mine stakeholders on their perceptions of work challenges. Descriptive statistics of mean and standard deviation was utilised to analyse sociodemographic characteristics of participants. MSD incidence rates were estimated and the patterns of MSD incidence at different anatomical sites were also determined. The Cox proportional regression analyses were utilised to compare hazard ratios of MSD risks between the exposed cohorts and unexposed cohorts in the phase one incidence survey, alpha level was set at 0.05. Transcription, thematic and content analyses with the aid of Nvivo version 11 for windows was used to interpret stakeholders’ perception of work challenges. The incidence of MSD was 6.2 per 1000, with shoulder pain being the most reported complaint (40% prevalence). This was followed by back pain with the distribution of back pain presented as follows: upper back (20.37%), lower back (45.50%) and both (34.13%). All participants reported previous medical history of back, shoulder and neck pain. The relative risk ratio of mineworkers to MSDs was 4.57, which implies that the mineworkers were approximately 5 times more at risk of developing MSDs compared to the recruited unexposed cohorts. Meanwhile, wrist pain (43.58%) was the highest MSD complaints which lead miners to be absent from work, followed by knee and back with 35.42% and 21% respectively. Physical job risks, such as III working underground and squatting or kneeling at work were all significantly associated with MSDs recurrence in all six body parts (HR: 1.12-1.92, 95%CI). Similarly, time pressure to complete task, low decision latitude, poor job satisfaction, somatisation and mental disorder, job insecurity, poor incentive system (HR: 1.01-1.75, 95%CI) were perceived by stakeholders’ and participants alike in the study to be significantly associated with MSDs incidence. Quarrymen are exposed to high MSD risks associated with elevated psychosocial stress from their difficult work situations. The South Eastern Nigerian mine stakeholders believed that the high incidence of MSDs may have a substantial impact on health and productivity in the near future. Necessitating a clear need for the promotion of stakeholder’s engagement concerning safe work policy implementation initiatives in the sector.
- Full Text:
- Date Issued: 2020
- Authors: Egwuonwu, Victor Afamerfuna
- Date: 2020
- Subjects: Quarries and quarrying -- Health aspects -- Nigeria , Musculoskeletal system -- Diseases -- Nigeria , Miners -- Health and hygiene -- Nigeria
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/141263 , vital:37957
- Description: Musculoskeletal disorders (MSDs) are very common among industrial labourers, leading to sick leave absence, disability and low productivity at work. MSDs have multifactorial causes, thereby making it difficult to pinpoint the extent of the contributions of the various risks regarding the mechanism of its pathophysiology. Previously, attempts were made to study regional pain symptoms in varying occupational groups, disregarding the particularities of the different workplace situations. It is important to highlight, that quantifying physical exposure factors that contribute to MSDs occurrence using quantitative approach alone could be inadequate. It is therefore imperative to incorporate qualitative approach to unmask accompanying psychosocial stressors, which are mostly explanatory variables. The study investigated the following: 12-month retrospective prevalence of MSDs, prospective incidence, risk factors and pattern of MSDs in a 6-month follow-up survey of selected quarry mineworkers, who reported MSDs complaints at the mine clinic. The study also determined the level of psychosocial stress associated with working in the mine by understanding stakeholders’ perception of work challenges, and how it influenced recurrence of MSDs. The study utilised a mixed method design with two phases: phase 1 was an initial baseline retrospective prevalence and a prospective cohort-control incidence survey. The Cultural and Psychosocial Influence on Disability (CUPID) questionnaire was translated into an Igbo-language version, cross-culturally adapted and utilized. The instrument was administered via oral interview and sought information on the following: demographic characteristics; pain in different anatomical sites and associated disability for tasks of daily living; as well as information on any change of job and reason during the study period, recent pain in different anatomical sites and associated disability for tasks of daily living; distress from common somatic symptoms; mental health status, sickness absence in the past 5-months for musculoskeletal pain. Phase 2 was a qualitative focus group discussion that engaged mine stakeholders on their perceptions of work challenges. Descriptive statistics of mean and standard deviation was utilised to analyse sociodemographic characteristics of participants. MSD incidence rates were estimated and the patterns of MSD incidence at different anatomical sites were also determined. The Cox proportional regression analyses were utilised to compare hazard ratios of MSD risks between the exposed cohorts and unexposed cohorts in the phase one incidence survey, alpha level was set at 0.05. Transcription, thematic and content analyses with the aid of Nvivo version 11 for windows was used to interpret stakeholders’ perception of work challenges. The incidence of MSD was 6.2 per 1000, with shoulder pain being the most reported complaint (40% prevalence). This was followed by back pain with the distribution of back pain presented as follows: upper back (20.37%), lower back (45.50%) and both (34.13%). All participants reported previous medical history of back, shoulder and neck pain. The relative risk ratio of mineworkers to MSDs was 4.57, which implies that the mineworkers were approximately 5 times more at risk of developing MSDs compared to the recruited unexposed cohorts. Meanwhile, wrist pain (43.58%) was the highest MSD complaints which lead miners to be absent from work, followed by knee and back with 35.42% and 21% respectively. Physical job risks, such as III working underground and squatting or kneeling at work were all significantly associated with MSDs recurrence in all six body parts (HR: 1.12-1.92, 95%CI). Similarly, time pressure to complete task, low decision latitude, poor job satisfaction, somatisation and mental disorder, job insecurity, poor incentive system (HR: 1.01-1.75, 95%CI) were perceived by stakeholders’ and participants alike in the study to be significantly associated with MSDs incidence. Quarrymen are exposed to high MSD risks associated with elevated psychosocial stress from their difficult work situations. The South Eastern Nigerian mine stakeholders believed that the high incidence of MSDs may have a substantial impact on health and productivity in the near future. Necessitating a clear need for the promotion of stakeholder’s engagement concerning safe work policy implementation initiatives in the sector.
- Full Text:
- Date Issued: 2020
The impact of three different footwear conditions on individual biomechanical, physiological and perceptual responses during running.
- Authors: McDougall, Justin John
- Date: 2016
- Subjects: Running -- Physiological aspects , Running shoes -- Physiological aspects , Running -- Health aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5177 , http://hdl.handle.net/10962/d1019988
- Description: Background: Despite the introduction of running footwear in the 1970’s, running injury rates continue to be unacceptably high. The subsequent revival of barefoot running and the introduction of minimalist footwear occurred, in an attempt to reduce injury rates and increase performance. There is much contention in the literature around the effectiveness of these footwear conditions. Furthermore individual responses have recently been proposed to provide more accurate and reflective conclusions than the use of mean data. Objectives: Twofold: a) to compare the biomechanical, physiological and perceptual responses between the shod, minimalist and barefoot footwear conditions and b) to assess and compare individual responses under these footwear conditions. Methods: 26 well-trained, male, habitually shod endurance runners, aged between 18 - 30 years completed three experimental sessions on an indoor runway and motorized treadmill. Each session was completed in either the shod, minimalist or barefoot condition, running at 15km.h-1. Variables assessed included stride rate, stride length, impact peak, vertical impact and average loading rate and strike time (biomechanical); heart rate, oxygen consumption and electromyography (physiological); and rating of perceived exertion and body discomfort (perceptual). Results: Biomechanics – Stride rate and stride length showed a significant (p<0.001) increase and decrease respectively when running in the minimalist or barefoot conditions versus shod. Running barefoot versus the minimalist and shod conditions resulted in a significantly (p<0.001) greater vertical impact loading rate. Strike time was significantly (p=0.008) reduced running in the minimalist and barefoot conditions versus shod. Physiology – Running barefoot versus shod resulted in a significantly (p=0.02) reduced heart rate and Tibialis Anterior activity (p=0.005). There was a large variability in individual responses for many variables, with responders and non-responders seen. Conclusion: The study suggests that there are significant differences between all three forms of running for some variables. It was further noted that there is support for the proposal that individual responses are highly variable and should be analysed accordingly
- Full Text:
- Date Issued: 2016
- Authors: McDougall, Justin John
- Date: 2016
- Subjects: Running -- Physiological aspects , Running shoes -- Physiological aspects , Running -- Health aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5177 , http://hdl.handle.net/10962/d1019988
- Description: Background: Despite the introduction of running footwear in the 1970’s, running injury rates continue to be unacceptably high. The subsequent revival of barefoot running and the introduction of minimalist footwear occurred, in an attempt to reduce injury rates and increase performance. There is much contention in the literature around the effectiveness of these footwear conditions. Furthermore individual responses have recently been proposed to provide more accurate and reflective conclusions than the use of mean data. Objectives: Twofold: a) to compare the biomechanical, physiological and perceptual responses between the shod, minimalist and barefoot footwear conditions and b) to assess and compare individual responses under these footwear conditions. Methods: 26 well-trained, male, habitually shod endurance runners, aged between 18 - 30 years completed three experimental sessions on an indoor runway and motorized treadmill. Each session was completed in either the shod, minimalist or barefoot condition, running at 15km.h-1. Variables assessed included stride rate, stride length, impact peak, vertical impact and average loading rate and strike time (biomechanical); heart rate, oxygen consumption and electromyography (physiological); and rating of perceived exertion and body discomfort (perceptual). Results: Biomechanics – Stride rate and stride length showed a significant (p<0.001) increase and decrease respectively when running in the minimalist or barefoot conditions versus shod. Running barefoot versus the minimalist and shod conditions resulted in a significantly (p<0.001) greater vertical impact loading rate. Strike time was significantly (p=0.008) reduced running in the minimalist and barefoot conditions versus shod. Physiology – Running barefoot versus shod resulted in a significantly (p=0.02) reduced heart rate and Tibialis Anterior activity (p=0.005). There was a large variability in individual responses for many variables, with responders and non-responders seen. Conclusion: The study suggests that there are significant differences between all three forms of running for some variables. It was further noted that there is support for the proposal that individual responses are highly variable and should be analysed accordingly
- Full Text:
- Date Issued: 2016
The impact of low to moderate alcohol consumption on different types of human performance
- Authors: Goble, David
- Date: 2013
- Subjects: Alcohol -- Physiological effect Temperance Human information processing -- Effect of drugs on Visual perception -- Effect of drugs on Cognition -- Effect of drugs on Caffeine -- Physiological effect
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5136 , http://hdl.handle.net/10962/d1006042
- Description: Despite extensive research into the effects of alcohol consumption, there is no clear understanding into the mechanisms underlying human information processing impairment. The acute consumption of alcohol was investigated to determine the implications for human information processing capabilities, and to identify the extent to which these implications were stage-specific. Further aims included the investigation and quantification of caffeine-induced antagonism of alcohol impairment. Moreover, the aforementioned relationships were investigated in morning versus evening conditions. A test battery of six resource-specific tasks was utilised to measure visual perceptual, cognitive and sensory-motor performance, fashioned to return both simple and complex measures of each task. The tasks implemented were: visual perceptual performance (accommodation, visual detection, visual pattern recognition); cognition (memory recall- digit span); and motor output (modified Fitts‟ and a driving simulated line-tracking). Performance measures were recorded by the respective computer based tasks. Physiological variables measured included heart rate frequency, heart rate variability (RMSSD, High and Low Frequency Power) and body temperature. Saccade speed, saccade amplitude, pupil size and fixation duration were the oculomotor parameters measured. Three groups of participants (alcohol, caffeine+alcohol and control) n=36 were studied, split evenly between sexes in a mixed repeated/non-repeated measures design. The control group performed all test batteries under no influence. The alcohol group performed test batteries one and two sober, and three and four under the influence of a 0.4 g/kg dose of alcohol. Group caffeine+alcohol conducted test battery one sober, two under the effect of caffeine only (4 mg/kg), and three and four under the influence of both caffeine and alcohol (0.4 g/kg). The third test battery demonstrated the effects of alcohol during the inclining phase of the blood alcohol curve, and the fourth represented the declining phase. Morning experimentation occurred between 10:00 - 12: 45 and 10:30 -13:15 with evening experimentation between 19:00 - 21:30 and 19:30 - 22:00. Acute alcohol consumption at a dose of approximately 0.4 g/kg body weight effected an average peak breath alcohol concentration of 0.062 % and 0.059 % for the alcohol and caffeine+alcohol groups respectively. Task-related visual perceptual performance demonstrated significant decrements for simple reaction time, choice reaction time and error rate. Cognitive performance demonstrated no significant performance decrements, while motor performance indicated significant decrements in target accuracy only. Physiological parameters in response to alcohol consumption showed significantly decreased heart rate variability (RMSSD) in the modified Fitts‟ task only. A significant decrease in saccade amplitude in the memory task was the only change in oculomotor parameters. Prior caffeine consumption demonstrated limited antagonism to task-related alcohol impairment, significantly improving performance only in reduced error rate while reading. Caffeine consumption showed stimulating effects on physiological parameters, significantly increasing heart rate and heart rate variability when compared to alcohol alone. The design of the tasks allows for comparison between complex and simple task performance, indicating resource utilisation and depletion. Complex tasks demonstrated higher resource utilisation, however with no statistical performance differences to simple tasks. Physiological parameters showed greater change in response to alcohol consumption, than did the performance measures. Alcohol consumption imposed significant changes in physiological and oculomotor parameters for cognitive tasks only, significantly increasing heart rate frequency and decreasing heart rate variability, skin temperature and saccade amplitude. Caffeine consumption showed no antagonism of alcohol-induced performance measures. Physiological measures showed that caffeine consumption imposed stimulating effects in only the neural reflex and memory tasks, significantly increasing heart rate frequency and heart rate variability. Prior caffeine consumption significantly decreased fixation duration in the memory task only. The time of day at which alcohol was consumed demonstrated significant performance and physiological implications. Results indicated that morning consumption of alcohol imposes greater decrements in performance and larger fluctuations in physiological parameters than the decrements in evening experimental sessions. It can be concluded that alcohol consumption at a dose of 0.4 g/kg affects all stages in the information processing chain. Task performance indicates that alcohol has a greater severity on the early stages of information processing. Conversely, under the influence of alcohol an increased task complexity induces greater effects on central stage information processing. In addition, caffeine consumption at a dose of 4 mg/kg prior to alcohol does not antagonise the alcohol-induced performance decrements.
- Full Text:
- Date Issued: 2013
- Authors: Goble, David
- Date: 2013
- Subjects: Alcohol -- Physiological effect Temperance Human information processing -- Effect of drugs on Visual perception -- Effect of drugs on Cognition -- Effect of drugs on Caffeine -- Physiological effect
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5136 , http://hdl.handle.net/10962/d1006042
- Description: Despite extensive research into the effects of alcohol consumption, there is no clear understanding into the mechanisms underlying human information processing impairment. The acute consumption of alcohol was investigated to determine the implications for human information processing capabilities, and to identify the extent to which these implications were stage-specific. Further aims included the investigation and quantification of caffeine-induced antagonism of alcohol impairment. Moreover, the aforementioned relationships were investigated in morning versus evening conditions. A test battery of six resource-specific tasks was utilised to measure visual perceptual, cognitive and sensory-motor performance, fashioned to return both simple and complex measures of each task. The tasks implemented were: visual perceptual performance (accommodation, visual detection, visual pattern recognition); cognition (memory recall- digit span); and motor output (modified Fitts‟ and a driving simulated line-tracking). Performance measures were recorded by the respective computer based tasks. Physiological variables measured included heart rate frequency, heart rate variability (RMSSD, High and Low Frequency Power) and body temperature. Saccade speed, saccade amplitude, pupil size and fixation duration were the oculomotor parameters measured. Three groups of participants (alcohol, caffeine+alcohol and control) n=36 were studied, split evenly between sexes in a mixed repeated/non-repeated measures design. The control group performed all test batteries under no influence. The alcohol group performed test batteries one and two sober, and three and four under the influence of a 0.4 g/kg dose of alcohol. Group caffeine+alcohol conducted test battery one sober, two under the effect of caffeine only (4 mg/kg), and three and four under the influence of both caffeine and alcohol (0.4 g/kg). The third test battery demonstrated the effects of alcohol during the inclining phase of the blood alcohol curve, and the fourth represented the declining phase. Morning experimentation occurred between 10:00 - 12: 45 and 10:30 -13:15 with evening experimentation between 19:00 - 21:30 and 19:30 - 22:00. Acute alcohol consumption at a dose of approximately 0.4 g/kg body weight effected an average peak breath alcohol concentration of 0.062 % and 0.059 % for the alcohol and caffeine+alcohol groups respectively. Task-related visual perceptual performance demonstrated significant decrements for simple reaction time, choice reaction time and error rate. Cognitive performance demonstrated no significant performance decrements, while motor performance indicated significant decrements in target accuracy only. Physiological parameters in response to alcohol consumption showed significantly decreased heart rate variability (RMSSD) in the modified Fitts‟ task only. A significant decrease in saccade amplitude in the memory task was the only change in oculomotor parameters. Prior caffeine consumption demonstrated limited antagonism to task-related alcohol impairment, significantly improving performance only in reduced error rate while reading. Caffeine consumption showed stimulating effects on physiological parameters, significantly increasing heart rate and heart rate variability when compared to alcohol alone. The design of the tasks allows for comparison between complex and simple task performance, indicating resource utilisation and depletion. Complex tasks demonstrated higher resource utilisation, however with no statistical performance differences to simple tasks. Physiological parameters showed greater change in response to alcohol consumption, than did the performance measures. Alcohol consumption imposed significant changes in physiological and oculomotor parameters for cognitive tasks only, significantly increasing heart rate frequency and decreasing heart rate variability, skin temperature and saccade amplitude. Caffeine consumption showed no antagonism of alcohol-induced performance measures. Physiological measures showed that caffeine consumption imposed stimulating effects in only the neural reflex and memory tasks, significantly increasing heart rate frequency and heart rate variability. Prior caffeine consumption significantly decreased fixation duration in the memory task only. The time of day at which alcohol was consumed demonstrated significant performance and physiological implications. Results indicated that morning consumption of alcohol imposes greater decrements in performance and larger fluctuations in physiological parameters than the decrements in evening experimental sessions. It can be concluded that alcohol consumption at a dose of 0.4 g/kg affects all stages in the information processing chain. Task performance indicates that alcohol has a greater severity on the early stages of information processing. Conversely, under the influence of alcohol an increased task complexity induces greater effects on central stage information processing. In addition, caffeine consumption at a dose of 4 mg/kg prior to alcohol does not antagonise the alcohol-induced performance decrements.
- Full Text:
- Date Issued: 2013
The impact of load and frequency on the biomechanical, physiological and perceptual responses to dynamic pushing
- Authors: Cripwell, Adam Michael
- Date: 2007
- Subjects: Work -- Physiological aspects , Psychophysiology , Human engineering , Biomechanics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5144 , http://hdl.handle.net/10962/d1008183 , Work -- Physiological aspects , Psychophysiology , Human engineering , Biomechanics
- Description: The objective of the present research was to establish the biomechanical, physiological and perceptual responses of male operators to dynamic pushing tasks. The pushing tasks were performed using an industrial pallet jack with varying load/frequency combinations, in a controlled laboratory environment. Thirty healthy male subjects comprised the sample. Experimental procedures were conducted utilising the Chatillon ™ Dynamometer to measure force output in the initial, sustained and ending phases. The K4b2 Ergospirometer was used to assess physiological responses (heart rate and oxygen consumption [V02])' Nine recorded forces and nine experimental conditions formed the basis of this study, with subjects required to push three loads (200kg, 350kg, 500kg) at three frequencies (1120 sec, 1/40 sec, 1/60 sec) at a speed of 3.6km.h-1 over 14 metres on a co-efficient of friction controlled walkway for six minutes. Gait analysis, along with perceptions of exertion (,Central ' and 'Local' RPE) were collected during the third and sixth minutes of each condition . Body discomfort and contribution were identified upon completion of each condition. The results demonstrated that load and frequency interacted to influence responses within each domain. Increasing loads required increased force output during each stage of the push, which had a concomitant effect on physiological and perceptual responses. Significant differences arose between the initial, sustained and ending forces for each load, showing the direct relationship between load and force exertion. The combination of heaviest load/quickest frequency required the greatest physiological output, exceeding recommended guidelines for heart rate, V02 and energy expenditure responses. Intermediate combinations required moderate and acceptable energy cost. Linear relationships were established between heart rate and oxygen consumption , as well as between load and V02 , thus providing industrial practitioners an opportunity to evaluate task demands in situ. The combination of high forces and elevated physiological responses increased the subjective rating of the condition. The results emphasise the need to holistically consider all contributing factors in a dynamic pushing task. Dynamic pushing tasks place biomechanical, physiological and perceptual demands on the human operator, which must be minimised in order to ensure that this form of manual materials handling becomes sustainable in the long term.
- Full Text:
- Date Issued: 2007
- Authors: Cripwell, Adam Michael
- Date: 2007
- Subjects: Work -- Physiological aspects , Psychophysiology , Human engineering , Biomechanics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5144 , http://hdl.handle.net/10962/d1008183 , Work -- Physiological aspects , Psychophysiology , Human engineering , Biomechanics
- Description: The objective of the present research was to establish the biomechanical, physiological and perceptual responses of male operators to dynamic pushing tasks. The pushing tasks were performed using an industrial pallet jack with varying load/frequency combinations, in a controlled laboratory environment. Thirty healthy male subjects comprised the sample. Experimental procedures were conducted utilising the Chatillon ™ Dynamometer to measure force output in the initial, sustained and ending phases. The K4b2 Ergospirometer was used to assess physiological responses (heart rate and oxygen consumption [V02])' Nine recorded forces and nine experimental conditions formed the basis of this study, with subjects required to push three loads (200kg, 350kg, 500kg) at three frequencies (1120 sec, 1/40 sec, 1/60 sec) at a speed of 3.6km.h-1 over 14 metres on a co-efficient of friction controlled walkway for six minutes. Gait analysis, along with perceptions of exertion (,Central ' and 'Local' RPE) were collected during the third and sixth minutes of each condition . Body discomfort and contribution were identified upon completion of each condition. The results demonstrated that load and frequency interacted to influence responses within each domain. Increasing loads required increased force output during each stage of the push, which had a concomitant effect on physiological and perceptual responses. Significant differences arose between the initial, sustained and ending forces for each load, showing the direct relationship between load and force exertion. The combination of heaviest load/quickest frequency required the greatest physiological output, exceeding recommended guidelines for heart rate, V02 and energy expenditure responses. Intermediate combinations required moderate and acceptable energy cost. Linear relationships were established between heart rate and oxygen consumption , as well as between load and V02 , thus providing industrial practitioners an opportunity to evaluate task demands in situ. The combination of high forces and elevated physiological responses increased the subjective rating of the condition. The results emphasise the need to holistically consider all contributing factors in a dynamic pushing task. Dynamic pushing tasks place biomechanical, physiological and perceptual demands on the human operator, which must be minimised in order to ensure that this form of manual materials handling becomes sustainable in the long term.
- Full Text:
- Date Issued: 2007
The impact of clothing and protective gear on biophysical, physiological, perceptual and performance responses of rugby players during a simulated rugby protocol
- Authors: Cannon, Michael-John
- Date: 2012
- Subjects: Protective clothing -- Rugby football -- Health aspects -- Research , Rugby football injuries -- Prevention -- Research , Sports injuries -- Prevention -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5124 , http://hdl.handle.net/10962/d1005202 , Protective clothing -- Rugby football -- Health aspects -- Research , Rugby football injuries -- Prevention -- Research , Sports injuries -- Prevention -- Research
- Description: Background: Clothing and protective gear worn during intermittent exercise has shown to increase physiological and perceptual responses, and negatively impact performance capacities, due to increased heat strain, suggested to hasten the onset of fatigue. However, the mechanisms of fatigue experienced in rugby remain unclear. Objectives: The aim of this study was establish whether clothing and protective gear worn during a simulated rugby protocol impacts players‘ biophysical, physiological, perceptual and performance responses. Methods: 15 registered university and school first XV rugby players with a mean (± SD) age of 20.9 years (± 1.9) volunteered to participate in the study. Testing was performed in a controlled laboratory setting, with temperatures having to be within the range of 16º C-22º C. The mean (± SD) ambient temperature was 17.6º C (± 1.6) for the control condition and 17.3º C (1.5) for the experimental condition. The mean (± SD) relative humidity was 65.2 % (± 9.5) for the control condition and 66.3 % (± 10.0) for the experimental condition. Player‘s performed two protocols of 80-minutes; a control condition (minimal clothing and protective gear) and an experimental condition (full clothing and protective gear). Physiological, perceptual and performance responses were measured at set intervals during the protocol, while biophysical responses were measured pre-, at half-time and post-protocol during a 3-minute EMG treadmill protocol. Results: Muscle activity significantly (p< 0.05) increased with increasing running speeds. There were no significant (p> 0.05) differences for muscle activity between conditions, except for the semitendinosus muscle, which was significantly (p< 0.05) higher during the control condition while running at high speeds. Players‘ heart rates, core temperatures and perceptual responses were significantly (p< 0.05) higher during the experimental condition, compared to the control condition. Performance responses were significantly (p< 0.05) lower during the experimental condition. Conclusion: The main driver of physiological and perceptual responses was the exercise itself. However, the additional clothing and protective gear exacerbated the responses, particularly towards the end stages of the protocol. This negatively impacted players‘ performance. Muscle activity appeared to be unaffected by increased body temperatures. However, core temperatures never reached critically high levels during either condition.
- Full Text:
- Date Issued: 2012
- Authors: Cannon, Michael-John
- Date: 2012
- Subjects: Protective clothing -- Rugby football -- Health aspects -- Research , Rugby football injuries -- Prevention -- Research , Sports injuries -- Prevention -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5124 , http://hdl.handle.net/10962/d1005202 , Protective clothing -- Rugby football -- Health aspects -- Research , Rugby football injuries -- Prevention -- Research , Sports injuries -- Prevention -- Research
- Description: Background: Clothing and protective gear worn during intermittent exercise has shown to increase physiological and perceptual responses, and negatively impact performance capacities, due to increased heat strain, suggested to hasten the onset of fatigue. However, the mechanisms of fatigue experienced in rugby remain unclear. Objectives: The aim of this study was establish whether clothing and protective gear worn during a simulated rugby protocol impacts players‘ biophysical, physiological, perceptual and performance responses. Methods: 15 registered university and school first XV rugby players with a mean (± SD) age of 20.9 years (± 1.9) volunteered to participate in the study. Testing was performed in a controlled laboratory setting, with temperatures having to be within the range of 16º C-22º C. The mean (± SD) ambient temperature was 17.6º C (± 1.6) for the control condition and 17.3º C (1.5) for the experimental condition. The mean (± SD) relative humidity was 65.2 % (± 9.5) for the control condition and 66.3 % (± 10.0) for the experimental condition. Player‘s performed two protocols of 80-minutes; a control condition (minimal clothing and protective gear) and an experimental condition (full clothing and protective gear). Physiological, perceptual and performance responses were measured at set intervals during the protocol, while biophysical responses were measured pre-, at half-time and post-protocol during a 3-minute EMG treadmill protocol. Results: Muscle activity significantly (p< 0.05) increased with increasing running speeds. There were no significant (p> 0.05) differences for muscle activity between conditions, except for the semitendinosus muscle, which was significantly (p< 0.05) higher during the control condition while running at high speeds. Players‘ heart rates, core temperatures and perceptual responses were significantly (p< 0.05) higher during the experimental condition, compared to the control condition. Performance responses were significantly (p< 0.05) lower during the experimental condition. Conclusion: The main driver of physiological and perceptual responses was the exercise itself. However, the additional clothing and protective gear exacerbated the responses, particularly towards the end stages of the protocol. This negatively impacted players‘ performance. Muscle activity appeared to be unaffected by increased body temperatures. However, core temperatures never reached critically high levels during either condition.
- Full Text:
- Date Issued: 2012
The impact of a one-hour self-selected nap opportunity on physiological and performance variables during a simulated night shift
- Authors: Davy, Jonathan Patrick
- Date: 2010
- Subjects: Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5123 , http://hdl.handle.net/10962/d1005201 , Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Description: Napping has been explored extensively as a means of counteracting the negative effects associated with shift work. A significant amount of this research has focused on the implementation of scheduled naps, with few studies considering flexible nap schemes. The current study therefore aimed to assess the effects of a flexible nap opportunity on the physiological, cognitive, performance, neurophysiological and subjective responses of a group of non shift workers over the course of a three-day simulated night shift regime. Additional foci were the effects of the nap condition on the extent of the circadian adaptation of the subjects to the irregular work schedule and the circadian-related influences associated with being awake during the night. 36 subjects – 18 males and 18 females – were recruited to participate in the current study. The data collection spanned twelve days, during which four, three-day long shift cycles were set up: three night shift cycles and one day shift cycle. During each night shift cycle, three separate experimental conditions were staggered, namely the nap condition, the no nap condition and a booster break condition (a collaborative study that completed the setup). The day shift served as a further comparison. Each cycle comprised of 12 subjects, which meant there were four subjects per condition during each cycle. The shifts were 8 hours in duration, with the no nap group following a standard break schedule evinced in industry. The three breaks taken during the shifts amounted to a total time of 1 hour. The nap group was afforded a 1 hour flexible nap opportunity between 00h00 and 03h00 with no other breaks. Therefore, both conditions had the same amount of work time. During the shifts, subjects performed two simple, low arousal tasks (beading and packing) and completed a test battery roughly every two hours which was comprised of physiological, performance, neurophysiological and subjective measures. It was found that the inclusion of the nap opportunity significantly improved output performance and response time during a low precision, modified Fitts tapping task over the course of three night shifts, relative to no napping. Physiologically, napping resulted in higher heart rate frequency measures by the end of the shifts, which were also accompanied by significant reductions in subjective sleepiness ratings during all iii the night shifts. The nap group’s responses in this case, did not differ significantly from those of the day shift. Both simple reaction time and memory performances improved as a result of the nap inclusion, but only during the third night shift. The majority of the measures included in the research also depicted the effects of the circadian rhythm, which was indicative of the pronounced effect that this natural biological down regulation has on performance during the night. Napping reduced the severity of these effects during beading performance and measures of subjective sleepiness. With regard to habituation, the nap opportunity also resulted in positive changes in the responses of beading performance, high precision response time, simple reaction time and both subjective sleepiness measures, relative to no napping. Sleep diary responses indicated that although sleep length and quality during the day were significantly reduced for both night-time conditions, recovery sleep (length and quality) for the nap group did not differ significantly from the no nap group. The findings of this research indicate that the inclusion of a flexible napping opportunity during the night shift had positive effects on some physiological, performance and subjective responses, and that this intervention is as beneficial as scheduled napping. Specifically, napping resulted in a significantly higher output during the beading task, relative to the no nap group despite the duration of work time being the same. As such the introduction of a flexible, self-selected nap opportunity is a practical, effective and individual-specific means of alleviating the negative effects of shift work, while improving certain performance parameters. Therefore, industries should consider its inclusion in their fatigue management programs. However, contextspecific considerations must be made, with regard work scheduling, individual differences and task demands when implementing such an intervention. This will ensure that its introduction will be well received and in time, lessen the health and work-related decrements associated with shift work.
- Full Text:
- Date Issued: 2010
- Authors: Davy, Jonathan Patrick
- Date: 2010
- Subjects: Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5123 , http://hdl.handle.net/10962/d1005201 , Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Description: Napping has been explored extensively as a means of counteracting the negative effects associated with shift work. A significant amount of this research has focused on the implementation of scheduled naps, with few studies considering flexible nap schemes. The current study therefore aimed to assess the effects of a flexible nap opportunity on the physiological, cognitive, performance, neurophysiological and subjective responses of a group of non shift workers over the course of a three-day simulated night shift regime. Additional foci were the effects of the nap condition on the extent of the circadian adaptation of the subjects to the irregular work schedule and the circadian-related influences associated with being awake during the night. 36 subjects – 18 males and 18 females – were recruited to participate in the current study. The data collection spanned twelve days, during which four, three-day long shift cycles were set up: three night shift cycles and one day shift cycle. During each night shift cycle, three separate experimental conditions were staggered, namely the nap condition, the no nap condition and a booster break condition (a collaborative study that completed the setup). The day shift served as a further comparison. Each cycle comprised of 12 subjects, which meant there were four subjects per condition during each cycle. The shifts were 8 hours in duration, with the no nap group following a standard break schedule evinced in industry. The three breaks taken during the shifts amounted to a total time of 1 hour. The nap group was afforded a 1 hour flexible nap opportunity between 00h00 and 03h00 with no other breaks. Therefore, both conditions had the same amount of work time. During the shifts, subjects performed two simple, low arousal tasks (beading and packing) and completed a test battery roughly every two hours which was comprised of physiological, performance, neurophysiological and subjective measures. It was found that the inclusion of the nap opportunity significantly improved output performance and response time during a low precision, modified Fitts tapping task over the course of three night shifts, relative to no napping. Physiologically, napping resulted in higher heart rate frequency measures by the end of the shifts, which were also accompanied by significant reductions in subjective sleepiness ratings during all iii the night shifts. The nap group’s responses in this case, did not differ significantly from those of the day shift. Both simple reaction time and memory performances improved as a result of the nap inclusion, but only during the third night shift. The majority of the measures included in the research also depicted the effects of the circadian rhythm, which was indicative of the pronounced effect that this natural biological down regulation has on performance during the night. Napping reduced the severity of these effects during beading performance and measures of subjective sleepiness. With regard to habituation, the nap opportunity also resulted in positive changes in the responses of beading performance, high precision response time, simple reaction time and both subjective sleepiness measures, relative to no napping. Sleep diary responses indicated that although sleep length and quality during the day were significantly reduced for both night-time conditions, recovery sleep (length and quality) for the nap group did not differ significantly from the no nap group. The findings of this research indicate that the inclusion of a flexible napping opportunity during the night shift had positive effects on some physiological, performance and subjective responses, and that this intervention is as beneficial as scheduled napping. Specifically, napping resulted in a significantly higher output during the beading task, relative to the no nap group despite the duration of work time being the same. As such the introduction of a flexible, self-selected nap opportunity is a practical, effective and individual-specific means of alleviating the negative effects of shift work, while improving certain performance parameters. Therefore, industries should consider its inclusion in their fatigue management programs. However, contextspecific considerations must be made, with regard work scheduling, individual differences and task demands when implementing such an intervention. This will ensure that its introduction will be well received and in time, lessen the health and work-related decrements associated with shift work.
- Full Text:
- Date Issued: 2010
The factors affecting self-regulation through the analysis of physiological, psychological and behavioural measures during task-switching
- Authors: Chaplin, Caley
- Date: 2013 , 2013-07-16
- Subjects: Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5135 , http://hdl.handle.net/10962/d1006027 , Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Description: Individuals are required to manage multiple tasks which require strategic allocation of time and effort to ensure goals are reached efficiently. By providing the worker with autonomy over their work, performance and worker well-being have improved. This increased control allows individuals to organize work according to the needs of the body, which prevents fatigue leading to improved productivity. When given the option, humans tend to switch between tasks frequently. This behaviour can be used to determine the change in self-regulation strategies. An understanding of human task-switching behaviour is important for the design of job rotation systems. However, there is a lack of evidence explaining the factors motivating the need to switch between tasks. This study aims to use physiological, subjective and behavioural measures to explain the factors influencing selfregulation through the act of task-switching. Three primary hypotheses were developed to explain the factors underlying taskswitching behaviour. It was hypothesized that the degree of boredom experienced, the effort required to perform the task and the resource usage induced by the task are factors responsible in deciding task switching behaviour. Participants (17 males and 17 females) switched freely between five different information-processing tasks for the 45 minutes. Participants were allowed to switch back and forth between tasks and did not have to conduct all five tasks. The following measures were recorded during the experiment: subjective measures of boredom, mental effort, task frustration and perceived performance of the tasks; energy consumption and physiological measures of effort (HR, HRV and body temperature) and behavioural measures, including duration and frequency of task. Perceived boredom was found to differ among the tasks and before and after the experiment. The average boredom rating at each task transition for all tasks exceeded a score of 2.5 out of a possible 4. There were no significant changes in physiological measures between the beginning and end of the task trials. However, changes in physiological measures showed a decrease in effort investment following task transition. Heart rate variability was lower for externally-paced tasks than for self-paced tasks, despite the differences in cognitive demands. The most frequent task-switch combination occurred between tasks of high and low cognitive demand. The least frequent task-switching combination occurred between tasks of similar characteristics, which produced no differences in physiological responses. Task-switching behaviour was influenced by the degree of boredom, and therefore more time was spent on less monotonous tasks. The level of physiological effort required for the task affected task-switching behaviour. Task switches were made before any changes in effort took place in an attempt to maintain task efficiency. It appears plausible that a task switch was made to reduce effort investment and activation levels. The type of information processing resources used by different tasks affected the task-switching combinations. Individuals tended to switch between tasks of differing resources so that those in limited supply were able to replenish. Therefore the findings from this study can potentially be used to improve the design of job rotation systems. Such improvements may enhance productivity and worker well-being by inhibiting the onset of down regulation and fatigue processes. This study showed that autonomy is necessary for individuals to regulate behaviour to suit human needs. , Microsoft� Office Word 2007 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Chaplin, Caley
- Date: 2013 , 2013-07-16
- Subjects: Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5135 , http://hdl.handle.net/10962/d1006027 , Human multitasking -- Physiological aspects , Human multitasking -- Psychological aspects , Fatigue , Boredom , Attention , Mental fatigue , Human information processing , Decision making , Labor productivity , Industrial hygiene , Employees -- Workload
- Description: Individuals are required to manage multiple tasks which require strategic allocation of time and effort to ensure goals are reached efficiently. By providing the worker with autonomy over their work, performance and worker well-being have improved. This increased control allows individuals to organize work according to the needs of the body, which prevents fatigue leading to improved productivity. When given the option, humans tend to switch between tasks frequently. This behaviour can be used to determine the change in self-regulation strategies. An understanding of human task-switching behaviour is important for the design of job rotation systems. However, there is a lack of evidence explaining the factors motivating the need to switch between tasks. This study aims to use physiological, subjective and behavioural measures to explain the factors influencing selfregulation through the act of task-switching. Three primary hypotheses were developed to explain the factors underlying taskswitching behaviour. It was hypothesized that the degree of boredom experienced, the effort required to perform the task and the resource usage induced by the task are factors responsible in deciding task switching behaviour. Participants (17 males and 17 females) switched freely between five different information-processing tasks for the 45 minutes. Participants were allowed to switch back and forth between tasks and did not have to conduct all five tasks. The following measures were recorded during the experiment: subjective measures of boredom, mental effort, task frustration and perceived performance of the tasks; energy consumption and physiological measures of effort (HR, HRV and body temperature) and behavioural measures, including duration and frequency of task. Perceived boredom was found to differ among the tasks and before and after the experiment. The average boredom rating at each task transition for all tasks exceeded a score of 2.5 out of a possible 4. There were no significant changes in physiological measures between the beginning and end of the task trials. However, changes in physiological measures showed a decrease in effort investment following task transition. Heart rate variability was lower for externally-paced tasks than for self-paced tasks, despite the differences in cognitive demands. The most frequent task-switch combination occurred between tasks of high and low cognitive demand. The least frequent task-switching combination occurred between tasks of similar characteristics, which produced no differences in physiological responses. Task-switching behaviour was influenced by the degree of boredom, and therefore more time was spent on less monotonous tasks. The level of physiological effort required for the task affected task-switching behaviour. Task switches were made before any changes in effort took place in an attempt to maintain task efficiency. It appears plausible that a task switch was made to reduce effort investment and activation levels. The type of information processing resources used by different tasks affected the task-switching combinations. Individuals tended to switch between tasks of differing resources so that those in limited supply were able to replenish. Therefore the findings from this study can potentially be used to improve the design of job rotation systems. Such improvements may enhance productivity and worker well-being by inhibiting the onset of down regulation and fatigue processes. This study showed that autonomy is necessary for individuals to regulate behaviour to suit human needs. , Microsoft� Office Word 2007 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The ergonomic assessment of two different pipette models and their effects on biomechanical, performance, and subjective outcomes
- Authors: Masoka, Bonolo
- Date: 2023-10-13
- Subjects: Musculoskeletal disorder , Pipettes Design , Laboratory work , Wrist Wounds and injuries , Human engineering , User-centered design
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424278 , vital:72139
- Description: While laboratory workers are essential in many industries, they are also at a high risk of developing musculoskeletal disorders (MSDs). Manual pipetting has been identified as the leading cause of MSDs in laboratories because it exposes operators to high forces, repetition, static muscular loading, and awkward wrist postures for prolonged periods. The main contributors to the high risk associated with manual pipetting are the design of manual pipettes and how they are used. A laboratory-based study was conducted to assess and compare the biomechanical, subjective, and performance responses of an ergonomically designed pipette model to those of a traditional model. In a simulated laboratory workstation, 20 individuals performed 40 repetitions of pipetting tasks using each pipette model. Dependent variables consisted of muscle activity (of the Abductor Pollicis Brevis, Opponens Pollicis, Extensor pollicis longus, Abductor pollicis longus, Extensor pollicis brevis, and brachioradialis muscles), wrist postures, time to task completion, perceived muscular exertion (measured using the Borg RPE scale), perceived comfort and usability, and user preference. The results revealed that an ergonomic modification to pipette design has some effect on biomechanical and subjective outcomes. The ergonomic model significantly reduced muscular loading of the Opponens pollicis, and Abductor pollicis brevis muscles. The ergonomic model also reduced radial deviation and was associated with better subjective responses, while the time to task completion did not change. This study found that an ergonomic modification to pipette design can improve user comfort and well-being without compromising performance. Overall, the findings emphasize the importance of addressing pipette design to reduce the MSD risk associated with manual pipetting, and the necessity for a user-centred approach to tool design. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Masoka, Bonolo
- Date: 2023-10-13
- Subjects: Musculoskeletal disorder , Pipettes Design , Laboratory work , Wrist Wounds and injuries , Human engineering , User-centered design
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424278 , vital:72139
- Description: While laboratory workers are essential in many industries, they are also at a high risk of developing musculoskeletal disorders (MSDs). Manual pipetting has been identified as the leading cause of MSDs in laboratories because it exposes operators to high forces, repetition, static muscular loading, and awkward wrist postures for prolonged periods. The main contributors to the high risk associated with manual pipetting are the design of manual pipettes and how they are used. A laboratory-based study was conducted to assess and compare the biomechanical, subjective, and performance responses of an ergonomically designed pipette model to those of a traditional model. In a simulated laboratory workstation, 20 individuals performed 40 repetitions of pipetting tasks using each pipette model. Dependent variables consisted of muscle activity (of the Abductor Pollicis Brevis, Opponens Pollicis, Extensor pollicis longus, Abductor pollicis longus, Extensor pollicis brevis, and brachioradialis muscles), wrist postures, time to task completion, perceived muscular exertion (measured using the Borg RPE scale), perceived comfort and usability, and user preference. The results revealed that an ergonomic modification to pipette design has some effect on biomechanical and subjective outcomes. The ergonomic model significantly reduced muscular loading of the Opponens pollicis, and Abductor pollicis brevis muscles. The ergonomic model also reduced radial deviation and was associated with better subjective responses, while the time to task completion did not change. This study found that an ergonomic modification to pipette design can improve user comfort and well-being without compromising performance. Overall, the findings emphasize the importance of addressing pipette design to reduce the MSD risk associated with manual pipetting, and the necessity for a user-centred approach to tool design. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
- Full Text:
- Date Issued: 2023-10-13
The efficacy of a community based eccentric hamstring strengthening program in peri-urban Black South African soccer players
- Authors: Ryan, Bennett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3573 , vital:20526
- Description: Introduction: Hamstring injury prevalence in soccer remains a major concern. Research in this context has focused on Caucasian populations with little attention given to other ethnic groups. The compatibility and applicability of such research to the South African context, particularly at an amateur level, may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. The aim of this investigation was therefore twofold. 1) Identify the lower extremity strength and performance profile of Peri-urban Amateur South African Players, and 2) Assess the efficacy of a community based intervention through the use of the Nordic Hamstring Exercise. Methods: 19 Black male Eastern Cape amateur players participated in a 12 week randomly controlled trial (9 = Control, 10 = Intervention). All participants completed regular training, while the intervention group, in addition, performed the Nordic Hamstring exercise post warm up. The incremental program design was taken from Mjolsnes et al. (2004), with a progressive increase in both sets and repetitions. Compliance was defined as completion of the required exercises for that session. Isokinetic strength evaluations (at 60°.s-1 and 180°.s-1) including assessment of peak torque and total work, as well as performance measures of countermovement and squat jump, were completed pre and post intervention, with the profile of the Peri-urban player the combined responses of both groups at baseline. Additionally, both the functional ratio (Eccentric Hamstrings/Concentric Quadriceps) and eccentric utilization ratio (Countermovement Jump/Squat Jump) were calculated. Results: Concentric quadriceps peak torque at baseline reported values of 195 (±22) Nm and 141 (±21) Nm at 60°.s-1 and 180°.s-1. Values of 162 (±21) Nm were observed for peak torque of the eccentric hamstrings at 60°.s-1, while 157 (±18) Nm was indicated at 180°.s-1. Mean functional ratio responses were observed as 0.83 (±0.11) and 1.12 (±0.16) for 60°.s-1 and 180°.s-1 respectively. Additionally, the eccentric utilization ratio responses were recorded as 1.04 (±0.08). Regarding the intervention, concentric quadriceps total work of the dominant limb significantly improved over the time course of experimentation within the intervention group. Other quadriceps variables, concentric hamstrings, squat jump capability and performance measures all reported no significant changes (p>0.05) over the course of assessment when compared to the control. Eccentric hamstrings peak torque observed significant improvements (p<0.05) of between 5.72 and 12.82 % within the intervention group, while the countermovement jump indicated a significant 15.59 % increase (p<0.05). Additionally, the functional ratio and the eccentric utilization ratio both indicated no significant changes (p>0.05), with a 2.48-7.66 % and 5.33 % improvement noted following completion of assessment. Conclusion: Isokinetic responses at baseline observed decreased quadriceps strength, and increased hamstring strength when compared to both amateur and professional populations examined in previous studies, for both isokinetic testing speeds. Additionally, performance measures indicated similar responses to other amateur populations. Regarding the intervention, significant improvements in eccentric hamstring peak torque and countermovement jump indicate the partial success of the present intervention. Additionally, while the functional ratio and eccentric utilization ratio reported no significant changes, improvements were noted within the intervention group while the control noted no change. The Nordic hamstring lower therefore resulted in strength improvements within the eccentric hamstrings, reported as a significant factor for injury risk, however, such changes were not sufficient to significantly impact the functional ratio. It can be concluded that community based programs within South Africa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. More research of this nature is required to provide scientific support for structures and guidelines for the peri-urban community based South African player, to ensure the efficacy of internationally successful interventions such as the Nordic exercise.
- Full Text:
- Date Issued: 2016
- Authors: Ryan, Bennett
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3573 , vital:20526
- Description: Introduction: Hamstring injury prevalence in soccer remains a major concern. Research in this context has focused on Caucasian populations with little attention given to other ethnic groups. The compatibility and applicability of such research to the South African context, particularly at an amateur level, may be minimal due to fundamental differences in physical characteristics, as well as complexities with regards to implementation. The aim of this investigation was therefore twofold. 1) Identify the lower extremity strength and performance profile of Peri-urban Amateur South African Players, and 2) Assess the efficacy of a community based intervention through the use of the Nordic Hamstring Exercise. Methods: 19 Black male Eastern Cape amateur players participated in a 12 week randomly controlled trial (9 = Control, 10 = Intervention). All participants completed regular training, while the intervention group, in addition, performed the Nordic Hamstring exercise post warm up. The incremental program design was taken from Mjolsnes et al. (2004), with a progressive increase in both sets and repetitions. Compliance was defined as completion of the required exercises for that session. Isokinetic strength evaluations (at 60°.s-1 and 180°.s-1) including assessment of peak torque and total work, as well as performance measures of countermovement and squat jump, were completed pre and post intervention, with the profile of the Peri-urban player the combined responses of both groups at baseline. Additionally, both the functional ratio (Eccentric Hamstrings/Concentric Quadriceps) and eccentric utilization ratio (Countermovement Jump/Squat Jump) were calculated. Results: Concentric quadriceps peak torque at baseline reported values of 195 (±22) Nm and 141 (±21) Nm at 60°.s-1 and 180°.s-1. Values of 162 (±21) Nm were observed for peak torque of the eccentric hamstrings at 60°.s-1, while 157 (±18) Nm was indicated at 180°.s-1. Mean functional ratio responses were observed as 0.83 (±0.11) and 1.12 (±0.16) for 60°.s-1 and 180°.s-1 respectively. Additionally, the eccentric utilization ratio responses were recorded as 1.04 (±0.08). Regarding the intervention, concentric quadriceps total work of the dominant limb significantly improved over the time course of experimentation within the intervention group. Other quadriceps variables, concentric hamstrings, squat jump capability and performance measures all reported no significant changes (p>0.05) over the course of assessment when compared to the control. Eccentric hamstrings peak torque observed significant improvements (p<0.05) of between 5.72 and 12.82 % within the intervention group, while the countermovement jump indicated a significant 15.59 % increase (p<0.05). Additionally, the functional ratio and the eccentric utilization ratio both indicated no significant changes (p>0.05), with a 2.48-7.66 % and 5.33 % improvement noted following completion of assessment. Conclusion: Isokinetic responses at baseline observed decreased quadriceps strength, and increased hamstring strength when compared to both amateur and professional populations examined in previous studies, for both isokinetic testing speeds. Additionally, performance measures indicated similar responses to other amateur populations. Regarding the intervention, significant improvements in eccentric hamstring peak torque and countermovement jump indicate the partial success of the present intervention. Additionally, while the functional ratio and eccentric utilization ratio reported no significant changes, improvements were noted within the intervention group while the control noted no change. The Nordic hamstring lower therefore resulted in strength improvements within the eccentric hamstrings, reported as a significant factor for injury risk, however, such changes were not sufficient to significantly impact the functional ratio. It can be concluded that community based programs within South Africa have the potential to be effective; however, there are many barriers to implementation, including, language, ethnic and cultural differences, while a lack of resources and infrastructure play a significant role in a lack of development. More research of this nature is required to provide scientific support for structures and guidelines for the peri-urban community based South African player, to ensure the efficacy of internationally successful interventions such as the Nordic exercise.
- Full Text:
- Date Issued: 2016