The effect of work-hardening on the physical work capacity of manual labourers within South African industry
- Authors: Jacka, Karen-Louise
- Date: 1997
- Subjects: Human engineering , Industrial accidents -- South Africa , Industrial safety -- South Africa , Musculoskeletal system -- Wounds and injuries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5165 , http://hdl.handle.net/10962/d1016237
- Description: South Africa is a labour-intensive industrially developing country. As a result, in excess of 200 000 workers suffer from musculoskeletal injuries in a year. Research is thus essential to develop more effective strategies in the reduction and rehabilitation of occupational musculoskeletal disorders within industry. It was the hypothesis of this study that by improving the physical work capacity of manual labourers, through participation in an occupation specific work-hardening programme, that the ergonomic stress index and therefore the occurrence of musculoskeletal injuries within industry, may be reduced. Twenty-five male Black and Coloured manual labourers volunteered to participate in this study. In addition to in situ task analyses, the subjects participated in cardiovascular and strength assessments in the laboratory, both pre- and post-participation in the ten-week work-hardening programme. The data were statistically analyzed in order to identify any significant • improvements in the workers' physical work capacity, as measured by cardiovascular, strength and perceptual responses, following the period of work-hardening. Two significant reductions were noted in measures of working heart rate together with significant improvements in grip strength and trunk strength tested at a velocity of 60°.sec·1 at the post-conditioning assessments. In conclusion, the ten-week work-hardening programme resulted in nominal improvements in all the cardiovascular measures and significant improvements in the subjects' strength performance. However, industrialists must recognise that this study dealt with only one aspect of reducing the ergonomic stress index at the workplace and realise that, in addition to this focus, it remains essential to design the task to fit the human operator.
- Full Text:
- Date Issued: 1997
- Authors: Jacka, Karen-Louise
- Date: 1997
- Subjects: Human engineering , Industrial accidents -- South Africa , Industrial safety -- South Africa , Musculoskeletal system -- Wounds and injuries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5165 , http://hdl.handle.net/10962/d1016237
- Description: South Africa is a labour-intensive industrially developing country. As a result, in excess of 200 000 workers suffer from musculoskeletal injuries in a year. Research is thus essential to develop more effective strategies in the reduction and rehabilitation of occupational musculoskeletal disorders within industry. It was the hypothesis of this study that by improving the physical work capacity of manual labourers, through participation in an occupation specific work-hardening programme, that the ergonomic stress index and therefore the occurrence of musculoskeletal injuries within industry, may be reduced. Twenty-five male Black and Coloured manual labourers volunteered to participate in this study. In addition to in situ task analyses, the subjects participated in cardiovascular and strength assessments in the laboratory, both pre- and post-participation in the ten-week work-hardening programme. The data were statistically analyzed in order to identify any significant • improvements in the workers' physical work capacity, as measured by cardiovascular, strength and perceptual responses, following the period of work-hardening. Two significant reductions were noted in measures of working heart rate together with significant improvements in grip strength and trunk strength tested at a velocity of 60°.sec·1 at the post-conditioning assessments. In conclusion, the ten-week work-hardening programme resulted in nominal improvements in all the cardiovascular measures and significant improvements in the subjects' strength performance. However, industrialists must recognise that this study dealt with only one aspect of reducing the ergonomic stress index at the workplace and realise that, in addition to this focus, it remains essential to design the task to fit the human operator.
- Full Text:
- Date Issued: 1997
Influence of macro- versus microcooling on the physiological and psychological performance of the human operator
- Authors: Heyns, Gerhardus Johannes
- Date: 1995
- Subjects: Cold -- Physiological effect , Temperature -- Physiological effect , Body temperature -- Regulation , Heat -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5167 , http://hdl.handle.net/10962/d1016247
- Description: This study evaluated the effect of a macro- versus a microcooling system on the cognitive, psychomotor and physiological performance of human operators. Male subjects (n = 24) were acclimatized for four days and then subjected to three different environmental conditions: hot ambient (40°C; 40% RH), microcooling and macrocooling. Each environmental condition was repeated twice; once under a rest condition and once while simulating a physical workload of 40 W. Four performance tests (reasoning, eye-hand coordination, memory, reaction time) were conducted once every hour for four hours. Five physiological measurements, viz rectal temperature, skin temperature, heart rate, total sweat loss and sweat rate, were taken. A significant difference existed between the physiological responses under the hot ambient condition and both cooling conditions. For all five physiological parameters he human operator benefitted substantially whatever the cooling condition. The psychological performance results indicated a greater benefit under the cooling conditions, though various external factors may have influenced responses. User perception showed that macrocooling was perceived to be the optimal method of cooling. The results showed that there was no difference in the extent to which both rectal temperature and heart rate (for rest and work conditions) decreased over the 4-hour study period with micro- and macrocooling. In the baseline hot environment both increase. Sweat rate was lowest when resting or working in a microcooled environment and at its highest in the hot baseline environment. Mean skin temperature was lowest (for rest and work conditions) with microcooling and highest in the hot baseline environment. Reaction time and memory/attention were the same under all three environmental conditions. Eye-hand coordination was better with cooling than without, but did not differ between the two cooling conditions. Reasoning ability was poorest under the hot baseline condition and best in the macrocooled environment. User perception showed that the subjects found macrocooling highly acceptable. Microcooling was found to be uncomfortable, particularly because cold air (18 - 21°C) entered the jacket at one point which caused numbness of the skin at that point. Jackets did not always fit subjects well and the umbilical cord restricted free movement.
- Full Text:
- Date Issued: 1995
- Authors: Heyns, Gerhardus Johannes
- Date: 1995
- Subjects: Cold -- Physiological effect , Temperature -- Physiological effect , Body temperature -- Regulation , Heat -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5167 , http://hdl.handle.net/10962/d1016247
- Description: This study evaluated the effect of a macro- versus a microcooling system on the cognitive, psychomotor and physiological performance of human operators. Male subjects (n = 24) were acclimatized for four days and then subjected to three different environmental conditions: hot ambient (40°C; 40% RH), microcooling and macrocooling. Each environmental condition was repeated twice; once under a rest condition and once while simulating a physical workload of 40 W. Four performance tests (reasoning, eye-hand coordination, memory, reaction time) were conducted once every hour for four hours. Five physiological measurements, viz rectal temperature, skin temperature, heart rate, total sweat loss and sweat rate, were taken. A significant difference existed between the physiological responses under the hot ambient condition and both cooling conditions. For all five physiological parameters he human operator benefitted substantially whatever the cooling condition. The psychological performance results indicated a greater benefit under the cooling conditions, though various external factors may have influenced responses. User perception showed that macrocooling was perceived to be the optimal method of cooling. The results showed that there was no difference in the extent to which both rectal temperature and heart rate (for rest and work conditions) decreased over the 4-hour study period with micro- and macrocooling. In the baseline hot environment both increase. Sweat rate was lowest when resting or working in a microcooled environment and at its highest in the hot baseline environment. Mean skin temperature was lowest (for rest and work conditions) with microcooling and highest in the hot baseline environment. Reaction time and memory/attention were the same under all three environmental conditions. Eye-hand coordination was better with cooling than without, but did not differ between the two cooling conditions. Reasoning ability was poorest under the hot baseline condition and best in the macrocooled environment. User perception showed that the subjects found macrocooling highly acceptable. Microcooling was found to be uncomfortable, particularly because cold air (18 - 21°C) entered the jacket at one point which caused numbness of the skin at that point. Jackets did not always fit subjects well and the umbilical cord restricted free movement.
- Full Text:
- Date Issued: 1995
Physiological, perceptual and performance responses to competitive stress in individual and team sports among youth sport participants
- Authors: Swart, Kamilla
- Date: 1995
- Subjects: Sports -- Psychological aspects , Competition (Psychology) in adolescence -- Testing , Stress in adolescence -- Testing , Anxiety in adolescence -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5169 , http://hdl.handle.net/10962/d1016257
- Description: Due to limited research in the field testing of youth sport, specifically with regard to females, this project was delimited to the examination of the responses of youth participants in relation to the nature of the sport, when participating under conditions of competitive stress. It further attempted to elucidate gender related differences within these responses. Forty four male and female subjects aged 15 - 19 years volunteered to participate in this study; all pupils were First team members who competed in a variety of team and individual sports. Subjects participated in a battery of psychological, physiological and performance tests before and after competing in a practice session and during competitive league matches. The data were statistically analyzed for the various parameters under investigation. The results of the Sport Competition Anxiety Test indicated that the females, and the male team players had the highest competitive anxiety traits (CTA). The Task and Ego Orientation in Sport Questionnaire scores showed that most subjects have a general dominance of task orientation to sport. The results of the Physical Self-Perception Profile revealed that the females' poorer perception of their physical was not as substantial as their difference in CTA compared to males. Team participants, particularly the males, had a poorer self-image than individual sport counterparts. Elevated heart rate responses were observed prior to performing in a competitive ambience, with significant increases in team, rather than individual, players. The Evaluation of Task Demands revealed that team players, especially the females, perceived the match demands as significantly higher than the individual athletes. No significant differences were observed in the players' Evaluation of Perceived Strain. Neither were any significant differences observed in the players' ratings of their performance. In conclusion, although differences appear to exist between male and female responses within a competitive ambience, the magnitude of difference was far more notable between team and individual responses to competitive stress, particularly for competitive matches as opposed to practice sessions.
- Full Text:
- Date Issued: 1995
- Authors: Swart, Kamilla
- Date: 1995
- Subjects: Sports -- Psychological aspects , Competition (Psychology) in adolescence -- Testing , Stress in adolescence -- Testing , Anxiety in adolescence -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5169 , http://hdl.handle.net/10962/d1016257
- Description: Due to limited research in the field testing of youth sport, specifically with regard to females, this project was delimited to the examination of the responses of youth participants in relation to the nature of the sport, when participating under conditions of competitive stress. It further attempted to elucidate gender related differences within these responses. Forty four male and female subjects aged 15 - 19 years volunteered to participate in this study; all pupils were First team members who competed in a variety of team and individual sports. Subjects participated in a battery of psychological, physiological and performance tests before and after competing in a practice session and during competitive league matches. The data were statistically analyzed for the various parameters under investigation. The results of the Sport Competition Anxiety Test indicated that the females, and the male team players had the highest competitive anxiety traits (CTA). The Task and Ego Orientation in Sport Questionnaire scores showed that most subjects have a general dominance of task orientation to sport. The results of the Physical Self-Perception Profile revealed that the females' poorer perception of their physical was not as substantial as their difference in CTA compared to males. Team participants, particularly the males, had a poorer self-image than individual sport counterparts. Elevated heart rate responses were observed prior to performing in a competitive ambience, with significant increases in team, rather than individual, players. The Evaluation of Task Demands revealed that team players, especially the females, perceived the match demands as significantly higher than the individual athletes. No significant differences were observed in the players' Evaluation of Perceived Strain. Neither were any significant differences observed in the players' ratings of their performance. In conclusion, although differences appear to exist between male and female responses within a competitive ambience, the magnitude of difference was far more notable between team and individual responses to competitive stress, particularly for competitive matches as opposed to practice sessions.
- Full Text:
- Date Issued: 1995
A study of balance and gait following stroke : implications for rehabilitation
- Authors: Turnbull, George Innes
- Date: 1994
- Subjects: Cerebrovascular disease -- Physical therapy , Gait disorders , Equilibrium (Physiology) , People with disabilities -- Rehabilitation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5168 , http://hdl.handle.net/10962/d1016251
- Description: This study examined: the features and extent of the gait velocity decrement following stroke; the nature of the balance disorder and; investigated relationships between gait and balance. Twenty, fully-ambulant, hemiplegic subjects (12 men and 8 women), with a mean age of 57.2 years (± 10.7), were compared with 20 age- and sex-matched controls. Spatiotemporal gait kinematics were measured at five walking speeds ranging from "very slow" to "very fast". Balance was then measured while subjects maintained a variety of weight shift postures both with feet parallel and then in diagonal positions similar to those assumed during the double support phases of gait. Location and variability of centre of pressure (CP) were measured and the ranges over which CP could be shifted were calculated. Stroke subjects walked very slowly with their "fastest" walking speed (0.5 stat/s ± 0.23) no different from the "slowest" speed (0.38 stat/s ± 0.11) of the controls (p > 0.05). Differences between the other parameters were also found, many of which could be attributed to the differences in walking speeds. However, where the subjects walked at similar velocities, the hemiplegic sample walked with quicker and shoner strides suggesting a "cautious" gait pattern. The single support asymmetry of the strokes decreased with increasing walking speed. The positions of CP in the hemiplegic sample were found to be significantly displaced towards the unaffected leg and deficiencies were found in posterior shifts (p < 0.05). Postural sway was significantly greater in the hemiplegic sample implying less stable balance and the ranges over which the hemiplegic sample shifted weight were significantly less than the controls. The diagonal weight shift tests revealed the difficulty the stroke subjects experienced in shifting CP posterolaterally over the affected leg. Significant correlations were detected confmning the presence of relationships between static balance performance and gait. However, these correlation findings left considerable percentages of variance unexplained. These findings suggest that future rehabilitation should address the poverty of range of walking speed possessed by hemiplegic subjects as well as the reduced ability to weight shift over the hemiplegic limb, particularly posterolaterally. Further study to test these proposals is indicated.
- Full Text:
- Date Issued: 1994
- Authors: Turnbull, George Innes
- Date: 1994
- Subjects: Cerebrovascular disease -- Physical therapy , Gait disorders , Equilibrium (Physiology) , People with disabilities -- Rehabilitation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5168 , http://hdl.handle.net/10962/d1016251
- Description: This study examined: the features and extent of the gait velocity decrement following stroke; the nature of the balance disorder and; investigated relationships between gait and balance. Twenty, fully-ambulant, hemiplegic subjects (12 men and 8 women), with a mean age of 57.2 years (± 10.7), were compared with 20 age- and sex-matched controls. Spatiotemporal gait kinematics were measured at five walking speeds ranging from "very slow" to "very fast". Balance was then measured while subjects maintained a variety of weight shift postures both with feet parallel and then in diagonal positions similar to those assumed during the double support phases of gait. Location and variability of centre of pressure (CP) were measured and the ranges over which CP could be shifted were calculated. Stroke subjects walked very slowly with their "fastest" walking speed (0.5 stat/s ± 0.23) no different from the "slowest" speed (0.38 stat/s ± 0.11) of the controls (p > 0.05). Differences between the other parameters were also found, many of which could be attributed to the differences in walking speeds. However, where the subjects walked at similar velocities, the hemiplegic sample walked with quicker and shoner strides suggesting a "cautious" gait pattern. The single support asymmetry of the strokes decreased with increasing walking speed. The positions of CP in the hemiplegic sample were found to be significantly displaced towards the unaffected leg and deficiencies were found in posterior shifts (p < 0.05). Postural sway was significantly greater in the hemiplegic sample implying less stable balance and the ranges over which the hemiplegic sample shifted weight were significantly less than the controls. The diagonal weight shift tests revealed the difficulty the stroke subjects experienced in shifting CP posterolaterally over the affected leg. Significant correlations were detected confmning the presence of relationships between static balance performance and gait. However, these correlation findings left considerable percentages of variance unexplained. These findings suggest that future rehabilitation should address the poverty of range of walking speed possessed by hemiplegic subjects as well as the reduced ability to weight shift over the hemiplegic limb, particularly posterolaterally. Further study to test these proposals is indicated.
- Full Text:
- Date Issued: 1994
An ergonomic analysis of commercially available exercise equipment : implications for resistance training and clinical rehabilitation
- Authors: Scott, Stephen Bryce
- Date: 1994
- Subjects: Human engineering -- Case studies , Exercise -- Equipment and supplies -- Evaluation , Isometric exercise -- Evaluation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5172 , http://hdl.handle.net/10962/d1016367
- Description: This study examined the often contrived advertising claims of the manufacturers of variable resistance isotonic machinery. Specifically, the study sought to ascertain whether certain equipment was compatible with musculo-skeletal and perceptual needs and limitations of the human user: that is, to determine whether presently installed eccentric cams, which provide the variable resistance, matched the users force curves. The format of this research was in the ergonomic tradition in which empirical research is not necessarily the primary avenue. Consequently the inter-disciplinary nature of ergonomics required small-scale laboratory- simulation experiments to be conducted in a diverse range of disciplines such as physiology, psychology and biomechanics. It was found that on all five pieces of variable resistance machinery analysed, a mismatch between the force curves and the eccentric cams exist. The cams were redesigned accordingly. The metabolic cost of performing fixed-rate isoinertial lifts was moderate. The psychophysical analysis revealed that perceptual responses indicated that the work was classified as 'light' and only at 30% stress levels do local cues begin to dominate. Based on these findings it was concluded that manufacturers advertising claims in the instances analysed were not well-founded and that variable resistance isotonic machinery should only be used to develop muscular strength and endurance, and do not effectively serve as weight-loss devices.
- Full Text:
- Date Issued: 1994
- Authors: Scott, Stephen Bryce
- Date: 1994
- Subjects: Human engineering -- Case studies , Exercise -- Equipment and supplies -- Evaluation , Isometric exercise -- Evaluation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5172 , http://hdl.handle.net/10962/d1016367
- Description: This study examined the often contrived advertising claims of the manufacturers of variable resistance isotonic machinery. Specifically, the study sought to ascertain whether certain equipment was compatible with musculo-skeletal and perceptual needs and limitations of the human user: that is, to determine whether presently installed eccentric cams, which provide the variable resistance, matched the users force curves. The format of this research was in the ergonomic tradition in which empirical research is not necessarily the primary avenue. Consequently the inter-disciplinary nature of ergonomics required small-scale laboratory- simulation experiments to be conducted in a diverse range of disciplines such as physiology, psychology and biomechanics. It was found that on all five pieces of variable resistance machinery analysed, a mismatch between the force curves and the eccentric cams exist. The cams were redesigned accordingly. The metabolic cost of performing fixed-rate isoinertial lifts was moderate. The psychophysical analysis revealed that perceptual responses indicated that the work was classified as 'light' and only at 30% stress levels do local cues begin to dominate. Based on these findings it was concluded that manufacturers advertising claims in the instances analysed were not well-founded and that variable resistance isotonic machinery should only be used to develop muscular strength and endurance, and do not effectively serve as weight-loss devices.
- Full Text:
- Date Issued: 1994
Effects of an enriched physical activity programme on selected anthropometric, physiological and performance characteristics of an underprivilieged ethnic group
- Authors: Van Rooyen, Frederick
- Date: 1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:21115 , http://hdl.handle.net/10962/6455
- Description: Fifty pre-pubescent Xhosa-speaking children from two primary schools within the township of Rini, Grahamstown, were selected in this study to determine the effects, if any, of an enriched physical activity programme. Subjects were divided into experimental and control groups with only the experimental group physically participating in the enrichment programme. Selected anthropometric, physiological and motor performance tests were administered on both groups, before and after the programme, to monitor the effect of the enrichment programme on growth, cardiovascular efficiency and physical performance. Somatotype ratings showed no change after the training programme. However body composition showed greater gains in fat mass in the control group and marked drops in fat mass and increases in lean body mass in the experimental group. Longer running distances, higher predicted VO2 max mean values and improved recovery heart rate (HR) as well as larger gains in relative power, absolute power and velocity were experienced by individuals who participated in the training programme. The performance of the experimental group in the two motor performance tests out-weighed by far the performance of the control group as a result of the additional programme. The enrichment programme not only produced a positive effect on body composition but also improved aerobic and anaerobic efficiency. Improvements in both motor performance tests favoured the experimental group.
- Full Text:
- Date Issued: 1994
- Authors: Van Rooyen, Frederick
- Date: 1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:21115 , http://hdl.handle.net/10962/6455
- Description: Fifty pre-pubescent Xhosa-speaking children from two primary schools within the township of Rini, Grahamstown, were selected in this study to determine the effects, if any, of an enriched physical activity programme. Subjects were divided into experimental and control groups with only the experimental group physically participating in the enrichment programme. Selected anthropometric, physiological and motor performance tests were administered on both groups, before and after the programme, to monitor the effect of the enrichment programme on growth, cardiovascular efficiency and physical performance. Somatotype ratings showed no change after the training programme. However body composition showed greater gains in fat mass in the control group and marked drops in fat mass and increases in lean body mass in the experimental group. Longer running distances, higher predicted VO2 max mean values and improved recovery heart rate (HR) as well as larger gains in relative power, absolute power and velocity were experienced by individuals who participated in the training programme. The performance of the experimental group in the two motor performance tests out-weighed by far the performance of the control group as a result of the additional programme. The enrichment programme not only produced a positive effect on body composition but also improved aerobic and anaerobic efficiency. Improvements in both motor performance tests favoured the experimental group.
- Full Text:
- Date Issued: 1994
Influence of blue/green versus red and white light sources on human dark adaptation and other selected visual functions
- Authors: Hendrikse, Egbert Johannes
- Date: 1994
- Subjects: Light -- Physiological effect Lighting Vision -- Research Night vision Visual acuity Color -- Physiological effect Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5146 , http://hdl.handle.net/10962/d1009497
- Description: Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
- Full Text:
- Date Issued: 1994
- Authors: Hendrikse, Egbert Johannes
- Date: 1994
- Subjects: Light -- Physiological effect Lighting Vision -- Research Night vision Visual acuity Color -- Physiological effect Color vision
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5146 , http://hdl.handle.net/10962/d1009497
- Description: Red interior lighting used to preserve dark-adaptation needs to be replaced in military applications by blue/green lighting which is not detectable by 3rd-generation image intensifiers. This study investigated the influence of blue/green as compared to red and white light of equal photopic intensity on subsequent visual acuity , contrast sensitivity and dark-adaptation. Male subjects (n = 90) were assigned to one of 15 treatment conditions (n = 6) as determined by the colour (blue/green, red or white) and intensity (0.1; 0.4; 1.6; 6.4 and 25.6 cd/m²) of the pre-adaptation stimuli. A modified Goldmann/Weekers adaptometer was used to present the preadaptation stimuli, test stimuli and record visual (luminance) thresholds of each subject. Blue/green lighting had the same affect on visual (photopic) acuity and contrast sensitivity as white and red lighting. Blue/green affected visual (absolute) threshold at the start and during the process of dark-adaptation in the same manner as white but not the same as red lighting. White and red lighting did not differ significantly (p < 0.01) at low intensities (mesopic range) but did at the higher intensities (photopic range). After exposure to blue/green and white light, it will take longer to reach the same level of dark-adaptation than after exposure to red. These time differences increase with" increased intensities. The brightness ratio between red and white lights to produce the same dark-adaptation increases with an increase in intensity. At the upper mesopic region the differences between the effects of white and red lighting on subsequent dark-adaptation become irregular due to the inability to accurately equate non-monochromatic lights in the mesopic range.
- Full Text:
- Date Issued: 1994
Lifestyle orientation of high versus low achievers in traditional school sports: an holistic analysis
- Authors: Davies, Simeon
- Date: 1994
- Subjects: School sports Achievement motivation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5147 , http://hdl.handle.net/10962/d1009501
- Description: One hundred and four subjects aged 16-18 years volunteered to participate in this study which sought to identify via an holistic model those factors that characterise the lifestyle orientations of high and low achievers (male and female) in traditional school sport. Subjects were evaluated with respect to their anthropometric, physiological, psychological and perceptual responses. The data were statistically analyzed by one way ANOVAS for significant differences in the following pairs; males and females, high and low achievers, Mhi (male high achievers) and Mlo (male low achievers), and Fhi (female high achievers) and Flo (female low achievers). Anthropometric results indicate that Fhi and Flo were significantly different in their stature, mass and body fat, while Mhi and Mlo show no significant differences. A greater disparity existed between VO, max of Fhi and Flo compared with Mhi and Mlo, along with trends in heart rate and RPE responses that were also more divergent. Psychological responses indicate that Fhi and Flo were significantly different in five of the seven sub-domains of CATPA, while Mhi and Mlo were only identifiable in one. In the PSPP Fhi and Flo were significantly different in all five subscales, while Mhi and Mlo in only two. This contrast in variability between the paired group analysis of Fhi and Flo as compared to Mhi and Mlo appears throughout the data.
- Full Text:
- Date Issued: 1994
- Authors: Davies, Simeon
- Date: 1994
- Subjects: School sports Achievement motivation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5147 , http://hdl.handle.net/10962/d1009501
- Description: One hundred and four subjects aged 16-18 years volunteered to participate in this study which sought to identify via an holistic model those factors that characterise the lifestyle orientations of high and low achievers (male and female) in traditional school sport. Subjects were evaluated with respect to their anthropometric, physiological, psychological and perceptual responses. The data were statistically analyzed by one way ANOVAS for significant differences in the following pairs; males and females, high and low achievers, Mhi (male high achievers) and Mlo (male low achievers), and Fhi (female high achievers) and Flo (female low achievers). Anthropometric results indicate that Fhi and Flo were significantly different in their stature, mass and body fat, while Mhi and Mlo show no significant differences. A greater disparity existed between VO, max of Fhi and Flo compared with Mhi and Mlo, along with trends in heart rate and RPE responses that were also more divergent. Psychological responses indicate that Fhi and Flo were significantly different in five of the seven sub-domains of CATPA, while Mhi and Mlo were only identifiable in one. In the PSPP Fhi and Flo were significantly different in all five subscales, while Mhi and Mlo in only two. This contrast in variability between the paired group analysis of Fhi and Flo as compared to Mhi and Mlo appears throughout the data.
- Full Text:
- Date Issued: 1994
Plastic changes in spinal function of pre-pubescent scoliotic children engaged in an exercise therapy programme
- Authors: Solberg, Gill
- Date: 1993
- Subjects: Exercise therapy -- Methods , Scoliosis in children -- Exercise therapy -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5163 , http://hdl.handle.net/10962/d1015973
- Description: Previous studies of the effect of exercise therapy on scoliosis have demonstrated progression of spinal curves despite vigorous exercise regimens. This study presents evidence to the contrary. Ten children with functional scoliosis and attendant upper thoracic asymmetries were analyzed both before and after a specific exercise therapy programme, in order to determine the effect of the therapy on spinal functionality and the scoliotic curve. The effect of this intensive treatment, in which the subjects underwent a five-month exercise training programme with a total of 60 one-hour sessions, was investigated in a controlled clinical trial. A subjective and objective appraisal of posterior trunk asymmetry in schoolchildren aged 7-18 is reported. Selected functional and anthropometric measurements were made before and after the treatment, and antero-posterior x-rays were used to indicate changes in the scoliotic curve. New methods are described for quantifying the scoliotic curves in each child. Post-treatment tests showed a significant (p<0.05) decrease in Cobb's angles as well as a significant reduction in all the spinal and thoracic functional asymmetries observed in the study. The findings suggest that selective exercise programmes can contribute to improvement in cases of functional scoliosis. The study sheds new light on problems related to scoliosis and the benefits of exercise rehabilitation. Data on the incidence of scoliosis amongst 1052 black children are also presented and discussed.
- Full Text:
- Date Issued: 1993
- Authors: Solberg, Gill
- Date: 1993
- Subjects: Exercise therapy -- Methods , Scoliosis in children -- Exercise therapy -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5163 , http://hdl.handle.net/10962/d1015973
- Description: Previous studies of the effect of exercise therapy on scoliosis have demonstrated progression of spinal curves despite vigorous exercise regimens. This study presents evidence to the contrary. Ten children with functional scoliosis and attendant upper thoracic asymmetries were analyzed both before and after a specific exercise therapy programme, in order to determine the effect of the therapy on spinal functionality and the scoliotic curve. The effect of this intensive treatment, in which the subjects underwent a five-month exercise training programme with a total of 60 one-hour sessions, was investigated in a controlled clinical trial. A subjective and objective appraisal of posterior trunk asymmetry in schoolchildren aged 7-18 is reported. Selected functional and anthropometric measurements were made before and after the treatment, and antero-posterior x-rays were used to indicate changes in the scoliotic curve. New methods are described for quantifying the scoliotic curves in each child. Post-treatment tests showed a significant (p<0.05) decrease in Cobb's angles as well as a significant reduction in all the spinal and thoracic functional asymmetries observed in the study. The findings suggest that selective exercise programmes can contribute to improvement in cases of functional scoliosis. The study sheds new light on problems related to scoliosis and the benefits of exercise rehabilitation. Data on the incidence of scoliosis amongst 1052 black children are also presented and discussed.
- Full Text:
- Date Issued: 1993
The effects of a 160 km run on selected anthropometric, physiological and psychological parameters
- Authors: Oltmann, Carmen
- Date: 1992
- Subjects: Marathon running -- Psychological effects , Marathon running -- Physiological effects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5148 , http://hdl.handle.net/10962/d1009706 , Marathon running -- Psychological effects , Marathon running -- Physiological effects
- Description: Twenty-one male subjects volunteered to participate in this study of the effects of an ultramarathon run under competitive conditions. Selected anthropometric measurements were made before and after the race. Blood samples were taken before, and within 10 min. of completing the race. Haematocrit and cortisol concentrations were analysed from each sample. Three ratings of perceived exertion (RPE) - local, central and overall, were obtained at two-hourly intervals throughout the race. The shortened form of the Eysenck Personality Inventory (EPI) was administered before the race. The Profile of Mood States (POMS) test was completed both before and immediately after the race. The average running intensity was estimated to be about 32% VO₂max which would not have caused major lactate accumulation. Repetitive compressive forces as a result of heel-strike resulted in intervertebral disc fluid loss. This resulted in a significant (p<0.05) decrease in stature after the race. Mobilization of glycogen, trig1ycerides and protein for metabolism as well as fluid loss via sweat resulted in significantly decreased body mass after the race. Plasma volume and serum cortisol concentrations were significantly increased after the race compared to pre-race baseline levels. Local RPE responses were dominant throughout the entire race, followed by overall RPE. Running 160 km had an effect on mood state. "Depression", "fatigue" and "confusion" (profile of Mood states) were all significantly increased compared to pre-race scores. Sleep deprivation as a result of running through the night was probably an important contributing factor. The anthropometric profile of the ultramarathon runners in this sample was more like that of the general population than elite marathon runners from the literature. The ultramarathon runners were more extroverted than elite marathon runners, but exhibited a similar Profile of Mood state before the race. The stressor - running 160 km - resulted in a 'strain response'. This was evident in the decreased stature and mass, and increased serum cortisol, "depression", "confusion" and above all "fatigue".
- Full Text:
- Date Issued: 1992
- Authors: Oltmann, Carmen
- Date: 1992
- Subjects: Marathon running -- Psychological effects , Marathon running -- Physiological effects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5148 , http://hdl.handle.net/10962/d1009706 , Marathon running -- Psychological effects , Marathon running -- Physiological effects
- Description: Twenty-one male subjects volunteered to participate in this study of the effects of an ultramarathon run under competitive conditions. Selected anthropometric measurements were made before and after the race. Blood samples were taken before, and within 10 min. of completing the race. Haematocrit and cortisol concentrations were analysed from each sample. Three ratings of perceived exertion (RPE) - local, central and overall, were obtained at two-hourly intervals throughout the race. The shortened form of the Eysenck Personality Inventory (EPI) was administered before the race. The Profile of Mood States (POMS) test was completed both before and immediately after the race. The average running intensity was estimated to be about 32% VO₂max which would not have caused major lactate accumulation. Repetitive compressive forces as a result of heel-strike resulted in intervertebral disc fluid loss. This resulted in a significant (p<0.05) decrease in stature after the race. Mobilization of glycogen, trig1ycerides and protein for metabolism as well as fluid loss via sweat resulted in significantly decreased body mass after the race. Plasma volume and serum cortisol concentrations were significantly increased after the race compared to pre-race baseline levels. Local RPE responses were dominant throughout the entire race, followed by overall RPE. Running 160 km had an effect on mood state. "Depression", "fatigue" and "confusion" (profile of Mood states) were all significantly increased compared to pre-race scores. Sleep deprivation as a result of running through the night was probably an important contributing factor. The anthropometric profile of the ultramarathon runners in this sample was more like that of the general population than elite marathon runners from the literature. The ultramarathon runners were more extroverted than elite marathon runners, but exhibited a similar Profile of Mood state before the race. The stressor - running 160 km - resulted in a 'strain response'. This was evident in the decreased stature and mass, and increased serum cortisol, "depression", "confusion" and above all "fatigue".
- Full Text:
- Date Issued: 1992
Apneic Bradycardia : terrestrial and aquatic responses in man under working conditions
- Authors: Manley, Elizabeth
- Date: 1989
- Subjects: Apnea Respiration -- Measurement Heart rate monitoring Work -- Physiological aspects Underwater -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5098 , http://hdl.handle.net/10962/d1001838
- Description: The focus of this research was the reappraisal in physiological and psychophysical terms of current equivocal theories regarding the onset, course and termination of apneic bradycardia. Sixteen healthy male subjects participated in four separate testing sessions . Maximal oxygen consumption (VO₂ max) was measured on land and underwater using an identical direct, continuous progressive cycle ergometer test. On each of two other occasions subjects exercised in either environment at 50, 70 and 90% of the appropriate VO₂ max, during which time heart rate was continuously recorded. An initial apneic bout at each exercise intensity was followed by performance of the same workload without apnea for an equivalent period of time. Ratings of perceived exertion (RPE) were also monitored. While apneic bradycardia occurred at each exercise intensity studied underwater, it was apparent only at 50% VO₂ max on land. With the exception of between 50 and 90% VO₂ max on land, the mean apneic heart rates did not differ with varying exercise intensity (p<0.05); nor did the lowest heart rate recorded, although this was lower underwater than on land. Apart from 70% VO₂ max on land, apneic heart rates were lower than the equivalent values measured during exercise without apnea. Land and underwater heart rates during apneic and non-apneic conditions did not differ until 90% VO₂ max. The effects of increasing exercise intensity upon the onset of bradycardia were evident in that it occurred earlier at 50% VO₂ max underwater than at the heavier workloads, and only at 50% VO₂ max on land. The mean breath-hold duration did not differ between the land and underwater environments, nor was it affected by increasing exercise intensity. The order in which breath-holds was performed did not alter the length of apnea. Land and underwater RPE did not differ and increased with increasing exercise intensity in both environments. During apneic exercise RPE was greater than the equivalent exercise without apnea. Twelve of the original 16 subjects were divided equally into two groups on the basis of vital capacity expressed relative to body surface area. Vital capacity was measured during the first laboratory session. Neither the mean heart rate response to apneic exercise at 50% V0₂ max in both environments, nor the lowest heart rates recorded differed between groups, prompting the conclusion that lung volume did not affect apneic bradycardia. Despite a longer breath-hold duration for Group A (large relative lung volume) than Group B (small relative lung volume), the onset point of bradycardia was the same for either group when expressed relative to total breath-hold duration
- Full Text:
- Date Issued: 1989
- Authors: Manley, Elizabeth
- Date: 1989
- Subjects: Apnea Respiration -- Measurement Heart rate monitoring Work -- Physiological aspects Underwater -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5098 , http://hdl.handle.net/10962/d1001838
- Description: The focus of this research was the reappraisal in physiological and psychophysical terms of current equivocal theories regarding the onset, course and termination of apneic bradycardia. Sixteen healthy male subjects participated in four separate testing sessions . Maximal oxygen consumption (VO₂ max) was measured on land and underwater using an identical direct, continuous progressive cycle ergometer test. On each of two other occasions subjects exercised in either environment at 50, 70 and 90% of the appropriate VO₂ max, during which time heart rate was continuously recorded. An initial apneic bout at each exercise intensity was followed by performance of the same workload without apnea for an equivalent period of time. Ratings of perceived exertion (RPE) were also monitored. While apneic bradycardia occurred at each exercise intensity studied underwater, it was apparent only at 50% VO₂ max on land. With the exception of between 50 and 90% VO₂ max on land, the mean apneic heart rates did not differ with varying exercise intensity (p<0.05); nor did the lowest heart rate recorded, although this was lower underwater than on land. Apart from 70% VO₂ max on land, apneic heart rates were lower than the equivalent values measured during exercise without apnea. Land and underwater heart rates during apneic and non-apneic conditions did not differ until 90% VO₂ max. The effects of increasing exercise intensity upon the onset of bradycardia were evident in that it occurred earlier at 50% VO₂ max underwater than at the heavier workloads, and only at 50% VO₂ max on land. The mean breath-hold duration did not differ between the land and underwater environments, nor was it affected by increasing exercise intensity. The order in which breath-holds was performed did not alter the length of apnea. Land and underwater RPE did not differ and increased with increasing exercise intensity in both environments. During apneic exercise RPE was greater than the equivalent exercise without apnea. Twelve of the original 16 subjects were divided equally into two groups on the basis of vital capacity expressed relative to body surface area. Vital capacity was measured during the first laboratory session. Neither the mean heart rate response to apneic exercise at 50% V0₂ max in both environments, nor the lowest heart rates recorded differed between groups, prompting the conclusion that lung volume did not affect apneic bradycardia. Despite a longer breath-hold duration for Group A (large relative lung volume) than Group B (small relative lung volume), the onset point of bradycardia was the same for either group when expressed relative to total breath-hold duration
- Full Text:
- Date Issued: 1989
Effects of incremented loads over preferred values on psychophysical and selected gait kinematic factor
- Authors: Manley, Peter Gwynne
- Date: 1989
- Subjects: Psychophysiology , Kinematics , Work -- Physiological aspects , Human engineering
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5160 , http://hdl.handle.net/10962/d1015734
- Description: This study investigated the effects of incremented loads greater than maximal acceptable loads on selected locomotor kinematic and psychophysical variables for four different hand-held load-carriage methods. Ten male and ten female subjects, between the ages of 18 and 30, participated in four experimental sessions. Data collection involved obtaining selected anthropometric, strength, maximal load and preferred load, gait kinematic, and psychophysical values. The anthropometric, strength and load capacity variables enabled absolute and morphology normalised sex-based comparisons to be made. The kinematic and psychophysical parameters were used to quantify any changes from two sets of baseline values,"unloaded" and "maximal acceptable load" values, when loads were increased and carrying methods changed. Statistical analysis revealed that males were taller, heavier and stronger than females (p<0.05). Males chose significantly greater maximal acceptable loads and absolute maximal loads than females when expressed in their absolute or relative terms. Preferred walking speeds were not significantly different for unloaded or loaded conditions, although males walked significantly faster in absolute terms (but not in relative terms) than females. Different load carrying methods and incremented loads brought. about significant changes to several of the kinematic parameters investigated. Finally, ratings of perceived exertion, as well as the number of exertion sites, were seen to increase significantly as load increased. These values were not, however, significantly affected by differences in load carriage method.
- Full Text:
- Date Issued: 1989
- Authors: Manley, Peter Gwynne
- Date: 1989
- Subjects: Psychophysiology , Kinematics , Work -- Physiological aspects , Human engineering
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5160 , http://hdl.handle.net/10962/d1015734
- Description: This study investigated the effects of incremented loads greater than maximal acceptable loads on selected locomotor kinematic and psychophysical variables for four different hand-held load-carriage methods. Ten male and ten female subjects, between the ages of 18 and 30, participated in four experimental sessions. Data collection involved obtaining selected anthropometric, strength, maximal load and preferred load, gait kinematic, and psychophysical values. The anthropometric, strength and load capacity variables enabled absolute and morphology normalised sex-based comparisons to be made. The kinematic and psychophysical parameters were used to quantify any changes from two sets of baseline values,"unloaded" and "maximal acceptable load" values, when loads were increased and carrying methods changed. Statistical analysis revealed that males were taller, heavier and stronger than females (p<0.05). Males chose significantly greater maximal acceptable loads and absolute maximal loads than females when expressed in their absolute or relative terms. Preferred walking speeds were not significantly different for unloaded or loaded conditions, although males walked significantly faster in absolute terms (but not in relative terms) than females. Different load carrying methods and incremented loads brought. about significant changes to several of the kinematic parameters investigated. Finally, ratings of perceived exertion, as well as the number of exertion sites, were seen to increase significantly as load increased. These values were not, however, significantly affected by differences in load carriage method.
- Full Text:
- Date Issued: 1989
Energetic and kinematic responses to morphology-normalised speeds of walking and running
- Authors: Williams, Martin Andrew
- Date: 1989
- Subjects: Running -- Physiological aspects , Walking -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5166 , http://hdl.handle.net/10962/d1016240
- Description: This study investigated the influence of human morphology upon selected physiological, biomechanical and psychological responses to horizontal locomotion. In so doing, it was possible to evaluate the effectiveness with which morphology-normalised speeds of walking and running reduced the between-subject variability that is inherent in human locomotor responses. Twenty caucasian males were divided into two groups on the basis of stature - ten subjects in each of a "short" category (<170cm) and a "tall" category (>185cm). All subjects were habituated to treadmill locomotion prior to exposure to three walking treatments (0.83, 1.39 and 1.94m.s⁻¹) and three running treatments (2.50, 3.06 and 3.61m.s⁻¹). During each of these five-minute locomotor conditions, energetic (V02), kinematic (cadence and stride length) and psychophysical (central and local RPE) data were captured. From these data, lines of best fit were calculated for each subject, allowing for a prediction of the abovementioned locomotor variables from known absolute rates of progression. Using suitable regression equations, subject responses to morphology-normalised speeds of walking and running were effectively extrapolated. When the rate of progression was expressed in absolute terms (m.s⁻¹), significant differences (P <0.05) were found between the stature-related groups with respect to both energetic and kinematic locomotor responses. Such differences were successfully eliminated when use was made of locomotor speeds relativised on the basis of morphology. This study concludes that the use of appropriately prescribed morphology-normalised rates of progression are effective in reducing the variability in locomotor responses between subjects differing significantly in stature.
- Full Text:
- Date Issued: 1989
- Authors: Williams, Martin Andrew
- Date: 1989
- Subjects: Running -- Physiological aspects , Walking -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5166 , http://hdl.handle.net/10962/d1016240
- Description: This study investigated the influence of human morphology upon selected physiological, biomechanical and psychological responses to horizontal locomotion. In so doing, it was possible to evaluate the effectiveness with which morphology-normalised speeds of walking and running reduced the between-subject variability that is inherent in human locomotor responses. Twenty caucasian males were divided into two groups on the basis of stature - ten subjects in each of a "short" category (<170cm) and a "tall" category (>185cm). All subjects were habituated to treadmill locomotion prior to exposure to three walking treatments (0.83, 1.39 and 1.94m.s⁻¹) and three running treatments (2.50, 3.06 and 3.61m.s⁻¹). During each of these five-minute locomotor conditions, energetic (V02), kinematic (cadence and stride length) and psychophysical (central and local RPE) data were captured. From these data, lines of best fit were calculated for each subject, allowing for a prediction of the abovementioned locomotor variables from known absolute rates of progression. Using suitable regression equations, subject responses to morphology-normalised speeds of walking and running were effectively extrapolated. When the rate of progression was expressed in absolute terms (m.s⁻¹), significant differences (P <0.05) were found between the stature-related groups with respect to both energetic and kinematic locomotor responses. Such differences were successfully eliminated when use was made of locomotor speeds relativised on the basis of morphology. This study concludes that the use of appropriately prescribed morphology-normalised rates of progression are effective in reducing the variability in locomotor responses between subjects differing significantly in stature.
- Full Text:
- Date Issued: 1989
Ethical issues in human movement research
- Authors: Olivier, Stephen Chris
- Date: 1989
- Subjects: Human mechanics , Human mechanics -- Research -- Moral and ethical aspects , Research -- Moral and ethical aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5156 , http://hdl.handle.net/10962/d1015402
- Description: In acknowledging past abuses of humans in research contexts, and recognising the potential for malpractices in Human Movement Studies (HMS), this study evaluated the extent to which ethical issues are addressed in the discipline. The primary method consisted of the standard techniques of philosophic analysis, with empirical data complementing the conclusions. In general, the study contends that insufficient attention is paid to ethical issues in HMS research. In response to a set of specifically constructed, ethically problematic research proposals, only 1.8% of comments from senior researchers advocated rejection of the proposals on ethical grounds. Also, a journal search indicated that consideration of ethical issues in published research may largely be absent. Questionnaire responses revealed that South African HMS departments may be deficient in terms of accountability towards ethical guidelines. Whilst noting the existence of utilitarian ethics in HMS research, it is advocated that deontologic principles should take precedence. Further, only a sound educative effort will produce improvements. In conclusion, this study advocates a deontology-based approach to research ethics. This is consistent with the contention that the use of humans in research is a privilege, and that the rights of participants ought to outweigh the desire of researchers to conduct research.
- Full Text:
- Date Issued: 1989
- Authors: Olivier, Stephen Chris
- Date: 1989
- Subjects: Human mechanics , Human mechanics -- Research -- Moral and ethical aspects , Research -- Moral and ethical aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5156 , http://hdl.handle.net/10962/d1015402
- Description: In acknowledging past abuses of humans in research contexts, and recognising the potential for malpractices in Human Movement Studies (HMS), this study evaluated the extent to which ethical issues are addressed in the discipline. The primary method consisted of the standard techniques of philosophic analysis, with empirical data complementing the conclusions. In general, the study contends that insufficient attention is paid to ethical issues in HMS research. In response to a set of specifically constructed, ethically problematic research proposals, only 1.8% of comments from senior researchers advocated rejection of the proposals on ethical grounds. Also, a journal search indicated that consideration of ethical issues in published research may largely be absent. Questionnaire responses revealed that South African HMS departments may be deficient in terms of accountability towards ethical guidelines. Whilst noting the existence of utilitarian ethics in HMS research, it is advocated that deontologic principles should take precedence. Further, only a sound educative effort will produce improvements. In conclusion, this study advocates a deontology-based approach to research ethics. This is consistent with the contention that the use of humans in research is a privilege, and that the rights of participants ought to outweigh the desire of researchers to conduct research.
- Full Text:
- Date Issued: 1989
Identification and analysis of manual materials handling tasks within a commercial warehouse in South Africa
- Authors: Walraven, Lynne Louise
- Date: 1989
- Subjects: Materials handling -- Safety measures , Industrial safety -- South Africa , Lifting and carrying -- Safety measures
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5159 , http://hdl.handle.net/10962/d1015722
- Description: Lifting and overstraining are major causative factors related to musculoskeletal injuries and low back pain. A great number of work-related injuries arise from the handling and/or mishandling of materials. Hence there is a need to quantify risk factors in situ and develop guidelines for safe lifting practises in industry. The aim of this study was to make appropriate in situ quantification, within a commercial warehouse, of the stresses and physical demands imposed on the worker when performing two handed lifts in the sagittal plane. The performance of employees was assessed under normal working conditions through an observational methodology of data collection. Task performance evaluation was based on detailed measurement of all containers handled, an activity and time analysis, and the 'Work Practices Guide to Manual Lifting’ (NIOSH, 1981) which was used as the primary guide to developing theoretical recommendations to probable MMH risk factors for the workers involved. Of the 191 tasks analysed 103 were deemed unsuitable. Appropriate task factor adjustments were made where necessary to both the frequency and Hfactors (horizontal distance between the centre of gravity of the container and that of the worker) in order to reduce the risk factor for the workers
- Full Text:
- Date Issued: 1989
- Authors: Walraven, Lynne Louise
- Date: 1989
- Subjects: Materials handling -- Safety measures , Industrial safety -- South Africa , Lifting and carrying -- Safety measures
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5159 , http://hdl.handle.net/10962/d1015722
- Description: Lifting and overstraining are major causative factors related to musculoskeletal injuries and low back pain. A great number of work-related injuries arise from the handling and/or mishandling of materials. Hence there is a need to quantify risk factors in situ and develop guidelines for safe lifting practises in industry. The aim of this study was to make appropriate in situ quantification, within a commercial warehouse, of the stresses and physical demands imposed on the worker when performing two handed lifts in the sagittal plane. The performance of employees was assessed under normal working conditions through an observational methodology of data collection. Task performance evaluation was based on detailed measurement of all containers handled, an activity and time analysis, and the 'Work Practices Guide to Manual Lifting’ (NIOSH, 1981) which was used as the primary guide to developing theoretical recommendations to probable MMH risk factors for the workers involved. Of the 191 tasks analysed 103 were deemed unsuitable. Appropriate task factor adjustments were made where necessary to both the frequency and Hfactors (horizontal distance between the centre of gravity of the container and that of the worker) in order to reduce the risk factor for the workers
- Full Text:
- Date Issued: 1989
Physiological and psychophysical factors in the rating of perceived exertion during uphill overground and treadmill running
- Authors: Olivier, Stephen Chris
- Date: 1989
- Subjects: Physical fitness -- Measurement , Physical fitness -- Physiological aspects , Physical fitness -- Psychological aspects , Running -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5161 , http://hdl.handle.net/10962/d1015769
- Description: The purpose of this study was to examine possible differences between the field and laboratory ratings of perceived exertion (RPE) when the performance and physiological measures for the two conditions were equated. Furthermore, the interactive effects of local, central and overall RPE were examined. Finally, the question of the potential effects of attitudes on RPE was addressed. Eleven well-conditioned adult male marathon runners voluntarily participated in the study. After a period of treadmill habituation, biographical and anthropometric data were collected. This was followed by a VO₂ max test and a speed-matching session at 70% of VO₂ max to determine overground running speed at 3.8% and 7. 5% grade. Subjects then completed an attitudinal questionnaire and ran 4km overground. Finally, the above test was repeated on the treadmill, with the gradient and running speed of the overground condition being replicated. Physiological measures and differentiated RPE were obtained during the final two sessions. There were no physical environmental, task characteristic or performance differences between the overground and treadmill conditions. No heart rate or VO₂ differences were observed between the two conditions, but VE was significantly elevated in the laboratory. Local and overall RPE were significantly higher in the laboratory than in the field, but there was no difference for central RPE. Attitudes were more favourable towards the field than towards the laboratory work task. The results suggest that neither heart rate nor VO₂ are major factors directly influencing the perception of exertion. VE however appears to be a potent central signal mediating RPE. The results also indicate that local factors play a more important role in the perception of exertion than was previously thought. Attitudes towards a work task could possibly mediate the self-reports of exertion. The findings of this study also suggest that RPE are influenced by cognition to a large degree. Finally, environmental cues, or the ambience of a particular working environment, can exert a substantial influence on RPE. Direct perceptual translations from laboratory to field situations may therefore be invalid.
- Full Text:
- Date Issued: 1989
- Authors: Olivier, Stephen Chris
- Date: 1989
- Subjects: Physical fitness -- Measurement , Physical fitness -- Physiological aspects , Physical fitness -- Psychological aspects , Running -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5161 , http://hdl.handle.net/10962/d1015769
- Description: The purpose of this study was to examine possible differences between the field and laboratory ratings of perceived exertion (RPE) when the performance and physiological measures for the two conditions were equated. Furthermore, the interactive effects of local, central and overall RPE were examined. Finally, the question of the potential effects of attitudes on RPE was addressed. Eleven well-conditioned adult male marathon runners voluntarily participated in the study. After a period of treadmill habituation, biographical and anthropometric data were collected. This was followed by a VO₂ max test and a speed-matching session at 70% of VO₂ max to determine overground running speed at 3.8% and 7. 5% grade. Subjects then completed an attitudinal questionnaire and ran 4km overground. Finally, the above test was repeated on the treadmill, with the gradient and running speed of the overground condition being replicated. Physiological measures and differentiated RPE were obtained during the final two sessions. There were no physical environmental, task characteristic or performance differences between the overground and treadmill conditions. No heart rate or VO₂ differences were observed between the two conditions, but VE was significantly elevated in the laboratory. Local and overall RPE were significantly higher in the laboratory than in the field, but there was no difference for central RPE. Attitudes were more favourable towards the field than towards the laboratory work task. The results suggest that neither heart rate nor VO₂ are major factors directly influencing the perception of exertion. VE however appears to be a potent central signal mediating RPE. The results also indicate that local factors play a more important role in the perception of exertion than was previously thought. Attitudes towards a work task could possibly mediate the self-reports of exertion. The findings of this study also suggest that RPE are influenced by cognition to a large degree. Finally, environmental cues, or the ambience of a particular working environment, can exert a substantial influence on RPE. Direct perceptual translations from laboratory to field situations may therefore be invalid.
- Full Text:
- Date Issued: 1989
The effects of a South African Black youth jive on selected biophysical physiological and psycho-social parameters
- Authors: Masipa, Mochaki Deborah
- Date: 1989
- Subjects: Movement, Psychology of , Dance, Black -- Physiological aspects , Dance -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5158 , http://hdl.handle.net/10962/d1015682
- Description: This study investigated the effects of a South African Black youth jive on selected Biophysical, Physiological and Psycho-social parameters, using 31 Black youths, males and females (mean age 19.29 yrs) as subjects. All subjects participated in the pre- and post-programme testing protocols (acting as their own control) and in a 7-week jive programme. While the female subjects were significantly (p<0.05) heavier with a greater percentage body fat than their male counterparts, a two factor analysis of variance revealed no significant changes in body composition (p<0.05) of either sex group. However, significant improvements did occur in the cardio-respiratory . parameters of working and recovery heart rates, predicted V0₂ max, and the anaerobic capacity. Here, the males exhibited superior cardio-respiratory qualities and performed better in all motor fitness parameters except flexibility, where no significant sex difference occurred. Also, there were significant improvements in all motor fitness tests with the exception of power (as tested in the 18-Item Illinois test). No significant differences occurred between male and female psycho-social responses with no changes occurring after the 7- week programme. It can be concluded that involvement in the 7-week jive programme improved physiological parameters but failed to bring about alterations in the biophysical and psycho-social domains..
- Full Text:
- Date Issued: 1989
- Authors: Masipa, Mochaki Deborah
- Date: 1989
- Subjects: Movement, Psychology of , Dance, Black -- Physiological aspects , Dance -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5158 , http://hdl.handle.net/10962/d1015682
- Description: This study investigated the effects of a South African Black youth jive on selected Biophysical, Physiological and Psycho-social parameters, using 31 Black youths, males and females (mean age 19.29 yrs) as subjects. All subjects participated in the pre- and post-programme testing protocols (acting as their own control) and in a 7-week jive programme. While the female subjects were significantly (p<0.05) heavier with a greater percentage body fat than their male counterparts, a two factor analysis of variance revealed no significant changes in body composition (p<0.05) of either sex group. However, significant improvements did occur in the cardio-respiratory . parameters of working and recovery heart rates, predicted V0₂ max, and the anaerobic capacity. Here, the males exhibited superior cardio-respiratory qualities and performed better in all motor fitness parameters except flexibility, where no significant sex difference occurred. Also, there were significant improvements in all motor fitness tests with the exception of power (as tested in the 18-Item Illinois test). No significant differences occurred between male and female psycho-social responses with no changes occurring after the 7- week programme. It can be concluded that involvement in the 7-week jive programme improved physiological parameters but failed to bring about alterations in the biophysical and psycho-social domains..
- Full Text:
- Date Issued: 1989
The contribution of psychogenic factors limiting prolonged work performed at different relative intensities
- Authors: Rorke, Stafford Conroy
- Date: 1986
- Subjects: Physical fitness -- Measurement , Physical fitness -- Psychological aspects , Work measurement , Work -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5103 , http://hdl.handle.net/10962/d1004772 , Physical fitness -- Measurement , Physical fitness -- Psychological aspects , Work measurement , Work -- Psychological aspects
- Description: This study investigated the physiological and psychological limitations to prolonged work performed at different relative intensities, through the use of an eclectic integrative methodology. Ten young male caucasian subjects (mean V0₂ max. 60,0 ml.kg⁻¹.min⁻¹ ± 7,9) were randomly exposed to treadmill runs at each of four relative intensities, namely 55%, 65%, 75% and 85% of V0₂ maximum, with the instruction to run to the point of subjective discomfort at which they were no longer willing to continue. Physiological measures of oxygen consumption (V0₂), heart rate (HR), respiratory exchange ratio (R) , minute ventilation volume (Vi), breathing frequency (Vf), tidal volume (Vt) and psychological measures of Ratings of Perceived Exertion (RPE), Perceived Thermal Comfo·rt (PTC), Perceived Pain and Perceived Fatigue were recorded throughout the protocol. The relative intensity was held constant by slight decreases in treadmill speed as subjects fatigued, and through feedback from an on-line oxygen consumption computer-aided data acquisition system. Significant increases in both physiological and psychological measures occurred with increases in relative intensity (p<0,05). HR and Vf increased overtime (p<0,05) whilst Rand Vt decreased over time (p < 0,05) . All psychological ratings increased in intensity over time (p < 0,05). Mean endurance times to exhaustion were 243 minutes ± 70 at 55% relative intensity, 159 minutes ±37 at 65%, 96 minutes ±25 at 75 % and 23 minutes +- 8 at 85%, being within the range reported by earlier researchers . A regression equation for prediction of endurance time given a known relative intensity was developed for this sample: % V0₂ max. = 117,8 + (-10,6 x LN (time)) (where r = -0,91) Convergence rankings indicate the greater contribution of local factors in the overall gestalt of perceived exertion, pain and fatigue, with biomechanical limitations to prolonged work (running) strongly implicated . High inter correlations between psychological rating scales suggest the use of the scale considered most applicable to the task at hand and the psychological response measure required. A coefficient of multiple correlation of 0,94 established the close interrelationship amongst the physiological and psychological parameters measured. Pre- and post-test Fatigue Cluster Analysis questionnaires indicated that the most important clusters contributing toward the sensation of fatigue and subsequent decision to cease activity were Task Aversion and General Fatigue (r = 0,96), followed by Leg Fatigue and Thirst. Motivation, the task at hand and an attainable goal appear to be important considerations in prolonged work performance. Relative intensity appears a valid tool for use in prolonged work studies due to its high predictive capacity for endurance performance times (r=-0,91). It is concluded that workloads considerably below 55% of maximal aerobic capacity are indicated as acceptable workloads for an 8 hour working day.
- Full Text:
- Date Issued: 1986
- Authors: Rorke, Stafford Conroy
- Date: 1986
- Subjects: Physical fitness -- Measurement , Physical fitness -- Psychological aspects , Work measurement , Work -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5103 , http://hdl.handle.net/10962/d1004772 , Physical fitness -- Measurement , Physical fitness -- Psychological aspects , Work measurement , Work -- Psychological aspects
- Description: This study investigated the physiological and psychological limitations to prolonged work performed at different relative intensities, through the use of an eclectic integrative methodology. Ten young male caucasian subjects (mean V0₂ max. 60,0 ml.kg⁻¹.min⁻¹ ± 7,9) were randomly exposed to treadmill runs at each of four relative intensities, namely 55%, 65%, 75% and 85% of V0₂ maximum, with the instruction to run to the point of subjective discomfort at which they were no longer willing to continue. Physiological measures of oxygen consumption (V0₂), heart rate (HR), respiratory exchange ratio (R) , minute ventilation volume (Vi), breathing frequency (Vf), tidal volume (Vt) and psychological measures of Ratings of Perceived Exertion (RPE), Perceived Thermal Comfo·rt (PTC), Perceived Pain and Perceived Fatigue were recorded throughout the protocol. The relative intensity was held constant by slight decreases in treadmill speed as subjects fatigued, and through feedback from an on-line oxygen consumption computer-aided data acquisition system. Significant increases in both physiological and psychological measures occurred with increases in relative intensity (p<0,05). HR and Vf increased overtime (p<0,05) whilst Rand Vt decreased over time (p < 0,05) . All psychological ratings increased in intensity over time (p < 0,05). Mean endurance times to exhaustion were 243 minutes ± 70 at 55% relative intensity, 159 minutes ±37 at 65%, 96 minutes ±25 at 75 % and 23 minutes +- 8 at 85%, being within the range reported by earlier researchers . A regression equation for prediction of endurance time given a known relative intensity was developed for this sample: % V0₂ max. = 117,8 + (-10,6 x LN (time)) (where r = -0,91) Convergence rankings indicate the greater contribution of local factors in the overall gestalt of perceived exertion, pain and fatigue, with biomechanical limitations to prolonged work (running) strongly implicated . High inter correlations between psychological rating scales suggest the use of the scale considered most applicable to the task at hand and the psychological response measure required. A coefficient of multiple correlation of 0,94 established the close interrelationship amongst the physiological and psychological parameters measured. Pre- and post-test Fatigue Cluster Analysis questionnaires indicated that the most important clusters contributing toward the sensation of fatigue and subsequent decision to cease activity were Task Aversion and General Fatigue (r = 0,96), followed by Leg Fatigue and Thirst. Motivation, the task at hand and an attainable goal appear to be important considerations in prolonged work performance. Relative intensity appears a valid tool for use in prolonged work studies due to its high predictive capacity for endurance performance times (r=-0,91). It is concluded that workloads considerably below 55% of maximal aerobic capacity are indicated as acceptable workloads for an 8 hour working day.
- Full Text:
- Date Issued: 1986
Economy and efficiency of human locomotion
- Authors: Goslin, Brian Richard
- Date: 1985
- Subjects: Walking -- Physiological aspects , Running -- Physiological aspects , Human locomotion
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5142 , http://hdl.handle.net/10962/d1007177 , Walking -- Physiological aspects , Running -- Physiological aspects , Human locomotion
- Description: Human locomotor economy and efficiency are highly variable. This study investigated the role that stature plays in this variation, by evaluating metabolic and respiratory responses to walking and running at speeds set relative to one's stature. Four groups of subjects: male, high V0₂ max (n = 11); male, average V0₂ max (n = 10); female, high V0₂ max (n = 10); and female, average V0₂ max (n = 11) were habituated to treadmill locomotion prior to the measurement of maximal oxygen consumption (V0₂ max). The V0₂ max test entailed 1 km.h⁻¹ increases per min from 3 to 6 km.h⁻¹ walking, and 7 - 17 km.h⁻¹ running then 1% grade increments per min until exhaustion. On each of four other occasions, the subject walked or ran at 6 of a variety of relative speeds - walking at 0.5, 0.7, 0.9, 1.1, 1.3; running at 1.5, 1.7, 1.9 and for selected subjects 2.1, 2.3 and 2.5 statures.s⁻¹ ,and grades - 0%, +3%, -3%. Steady-state respiratory and metabolic responses, and treadmill speed were monitored by an on-line computer system developed for this study. Cadence and RPE were also monitored. All subjects demonstrated an exponential relationship between V0₂ and walking relative speed (st.s⁻¹) (RS) . V0₂ (ml.kg⁻¹.min⁻¹ ) = 4.747 * e(1.371*RS) During running this relationship was essentially linear . The variability of economy at relative speed (9.08%) and absolute speed (9. 01%) did not differ. Male and female subjects did not differ in response to absolute speed but females were more economical at relative speeds (p<0.05). Those with high and average aerobic capacity did not differ in locomotor economy at relative speed. Higher freely-chosen stride length was associated with a higher V0₂ response as velocity increased. The V0₂ of uphill walking was 1.4 times greater than that for downhill walking (running: 1.28 times) . Stride length decreased with increasing speed in uphill locomotion but the reverse was the case for downhill. The economy and efficiency of walking was greater than that of running. Walking economy was maximal between 0.7 and 0.9 st. s⁻¹. Running economy remained essentially unaffected by increased velocity. The setting of locomotor velocity relative to stature does not minimize inter-subject variability in metabolic and respiratory response .
- Full Text:
- Date Issued: 1985
- Authors: Goslin, Brian Richard
- Date: 1985
- Subjects: Walking -- Physiological aspects , Running -- Physiological aspects , Human locomotion
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5142 , http://hdl.handle.net/10962/d1007177 , Walking -- Physiological aspects , Running -- Physiological aspects , Human locomotion
- Description: Human locomotor economy and efficiency are highly variable. This study investigated the role that stature plays in this variation, by evaluating metabolic and respiratory responses to walking and running at speeds set relative to one's stature. Four groups of subjects: male, high V0₂ max (n = 11); male, average V0₂ max (n = 10); female, high V0₂ max (n = 10); and female, average V0₂ max (n = 11) were habituated to treadmill locomotion prior to the measurement of maximal oxygen consumption (V0₂ max). The V0₂ max test entailed 1 km.h⁻¹ increases per min from 3 to 6 km.h⁻¹ walking, and 7 - 17 km.h⁻¹ running then 1% grade increments per min until exhaustion. On each of four other occasions, the subject walked or ran at 6 of a variety of relative speeds - walking at 0.5, 0.7, 0.9, 1.1, 1.3; running at 1.5, 1.7, 1.9 and for selected subjects 2.1, 2.3 and 2.5 statures.s⁻¹ ,and grades - 0%, +3%, -3%. Steady-state respiratory and metabolic responses, and treadmill speed were monitored by an on-line computer system developed for this study. Cadence and RPE were also monitored. All subjects demonstrated an exponential relationship between V0₂ and walking relative speed (st.s⁻¹) (RS) . V0₂ (ml.kg⁻¹.min⁻¹ ) = 4.747 * e(1.371*RS) During running this relationship was essentially linear . The variability of economy at relative speed (9.08%) and absolute speed (9. 01%) did not differ. Male and female subjects did not differ in response to absolute speed but females were more economical at relative speeds (p<0.05). Those with high and average aerobic capacity did not differ in locomotor economy at relative speed. Higher freely-chosen stride length was associated with a higher V0₂ response as velocity increased. The V0₂ of uphill walking was 1.4 times greater than that for downhill walking (running: 1.28 times) . Stride length decreased with increasing speed in uphill locomotion but the reverse was the case for downhill. The economy and efficiency of walking was greater than that of running. Walking economy was maximal between 0.7 and 0.9 st. s⁻¹. Running economy remained essentially unaffected by increased velocity. The setting of locomotor velocity relative to stature does not minimize inter-subject variability in metabolic and respiratory response .
- Full Text:
- Date Issued: 1985
Validity and reliability of an objective test of cricket skills
- Authors: Stretch, Richard Aldworth
- Date: 1985
- Subjects: Cricket , Cricket -- Training , Athletic ability -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5134 , http://hdl.handle.net/10962/d1005625 , Cricket , Cricket -- Training , Athletic ability -- Testing
- Description: This study was conducted to assess the validity and reliability of four self-designed, objective tests of cricket batting, bowling, fielding and general ability skills. The batting test requires the batsman to hit a suspended ball at a target area as many times as possible in 60 seconds. His score is doubled to give his score for the batting test. In the bowling test the bowler is required to bowl ten balls at target areas marked on the pitch. Each delivery is recorded to give him a score out of 100. The fielding test requires the fielder to catch and field seven balls in a predetermined sequence. Each fielded ball that is not thrown through the target area incurs a penalty of three seconds. The total time taken is used to obtain the fielding test score out of 100. In the general ability test the player is required to hit a ball up and down twenty-five times. He then has to run along a predetermined path and field three balls and then bowl three balls at a target. A penalty of three seconds is added onto the time taken for each ball that does not pass through the target area. The actual score, out of 100, is determined from the total time taken. To determine the validity of the objective tests of batting, bowling, fielding and general ability, 155 subjects were subjectively assessed in these four categories by experienced coaches. The four objective tests were then conducted on these subjects and the scores compared. Forty-four subjects were assessed by experienced and inexperienced testers to determine the reliability of the tests when administered by different testers. To determine the reliability of the tests when repeatedly administered by one tester 23 subjects were assessed on five consecutive days. Significant correlations (p < 0,05) were found for the tests of validity between subjective and objective assessment (0,43 to 0,81) and the test for objectivity between experienced and inexperienced testers (0,41 to 0,78). A significant improvement (p < 0,05) in scores occurred during repeated testing, but most of this improvement took place between the first two tests. The results indicate that the tests are valid and reliable tests of cricket batting, bowling, fielding and general ability, if sufficient pre-test practice is allowed.
- Full Text:
- Date Issued: 1985
- Authors: Stretch, Richard Aldworth
- Date: 1985
- Subjects: Cricket , Cricket -- Training , Athletic ability -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5134 , http://hdl.handle.net/10962/d1005625 , Cricket , Cricket -- Training , Athletic ability -- Testing
- Description: This study was conducted to assess the validity and reliability of four self-designed, objective tests of cricket batting, bowling, fielding and general ability skills. The batting test requires the batsman to hit a suspended ball at a target area as many times as possible in 60 seconds. His score is doubled to give his score for the batting test. In the bowling test the bowler is required to bowl ten balls at target areas marked on the pitch. Each delivery is recorded to give him a score out of 100. The fielding test requires the fielder to catch and field seven balls in a predetermined sequence. Each fielded ball that is not thrown through the target area incurs a penalty of three seconds. The total time taken is used to obtain the fielding test score out of 100. In the general ability test the player is required to hit a ball up and down twenty-five times. He then has to run along a predetermined path and field three balls and then bowl three balls at a target. A penalty of three seconds is added onto the time taken for each ball that does not pass through the target area. The actual score, out of 100, is determined from the total time taken. To determine the validity of the objective tests of batting, bowling, fielding and general ability, 155 subjects were subjectively assessed in these four categories by experienced coaches. The four objective tests were then conducted on these subjects and the scores compared. Forty-four subjects were assessed by experienced and inexperienced testers to determine the reliability of the tests when administered by different testers. To determine the reliability of the tests when repeatedly administered by one tester 23 subjects were assessed on five consecutive days. Significant correlations (p < 0,05) were found for the tests of validity between subjective and objective assessment (0,43 to 0,81) and the test for objectivity between experienced and inexperienced testers (0,41 to 0,78). A significant improvement (p < 0,05) in scores occurred during repeated testing, but most of this improvement took place between the first two tests. The results indicate that the tests are valid and reliable tests of cricket batting, bowling, fielding and general ability, if sufficient pre-test practice is allowed.
- Full Text:
- Date Issued: 1985