Combined and additive effects of assembly tasks and constrained body postures
- Authors: Skelton, Sarah Anne
- Date: 2007
- Subjects: Musculoskeletal system -- Diseases , Human engineering , Posture , Posture disorders , Work -- Physiological aspects , Occupational diseases , Manual work , Job stress
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5107 , http://hdl.handle.net/10962/d1005185 , Musculoskeletal system -- Diseases , Human engineering , Posture , Posture disorders , Work -- Physiological aspects , Occupational diseases , Manual work , Job stress
- Description: Despite extensive research into musculoskeletal disorders (MSDs) they continue to plague workers. Manual materials handling (MMH), in particular the concurrence of load manipulation and awkward body posture, has been identified as a key factor in the onset of MSDs. Only a few studies have looked at the interaction between manipulation tasks and working posture during assembly tasks and as a result their relationship has not been widely explored. Assessing the stresses resulting from individual task factors and body posture in isolation and adding them together may be too simplified to estimate an overall risk profile, since this does not take into account that there may be a non-linear interaction in strain responses when manipulation task and body posture interact. Therefore, the present study investigated biophysical, physiological and psychophysical responses to combined tasks, rather than individual tasks of body posture and manipulative tasks. The objective of the research was to establish the interactive effects of constrained body postures and manipulative tasks and to identify whether a cumulative or compensatory reaction occurs during this interaction. Nine conditions were assessed in a laboratory setting, which included combinations of three working postures (standing, sitting and stooping) and three assembly tasks (torque wrenching, precision and no task). Thirty-six subjects were required to complete all nine conditions, with each condition lasting ninety seconds. Muscle activity was recorded for seven muscles from the upper extremity, trunk and lower extremity regions and was complemented by physiological (heart rate, tidal volume, minute ventilation, oxygen consumption, energy expenditure and breathing frequency) and psychophysical (body discomfort) data. At the completion of all nine conditions subjects completed a retrospective psychophysical rating questionnaire pertaining to discomfort felt during the conditions. Responses obtained for the different task and posture combinations revealed compensatory reactions (additive > combined) for most of the conditions assessed for the biomechanical and physiological responses. In the majority of cases for muscle activity, no significant differences were found between the combined and the additive effects (p < 0.05), while for the physiological responses there were mostly significant differences observed. Psychophysical responses indicated that there was a significant difference overall between the additive and combined effects. The results of this study demonstrate that in order to identify risk areas, manipulation tasks and constrained working postures may be considered either in isolation and added together (additive) or as a combined task, since there were very few significant differences observed between these two effects. Further studies are required, however, to provide conclusive evidence.
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- Authors: Skelton, Sarah Anne
- Date: 2007
- Subjects: Musculoskeletal system -- Diseases , Human engineering , Posture , Posture disorders , Work -- Physiological aspects , Occupational diseases , Manual work , Job stress
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5107 , http://hdl.handle.net/10962/d1005185 , Musculoskeletal system -- Diseases , Human engineering , Posture , Posture disorders , Work -- Physiological aspects , Occupational diseases , Manual work , Job stress
- Description: Despite extensive research into musculoskeletal disorders (MSDs) they continue to plague workers. Manual materials handling (MMH), in particular the concurrence of load manipulation and awkward body posture, has been identified as a key factor in the onset of MSDs. Only a few studies have looked at the interaction between manipulation tasks and working posture during assembly tasks and as a result their relationship has not been widely explored. Assessing the stresses resulting from individual task factors and body posture in isolation and adding them together may be too simplified to estimate an overall risk profile, since this does not take into account that there may be a non-linear interaction in strain responses when manipulation task and body posture interact. Therefore, the present study investigated biophysical, physiological and psychophysical responses to combined tasks, rather than individual tasks of body posture and manipulative tasks. The objective of the research was to establish the interactive effects of constrained body postures and manipulative tasks and to identify whether a cumulative or compensatory reaction occurs during this interaction. Nine conditions were assessed in a laboratory setting, which included combinations of three working postures (standing, sitting and stooping) and three assembly tasks (torque wrenching, precision and no task). Thirty-six subjects were required to complete all nine conditions, with each condition lasting ninety seconds. Muscle activity was recorded for seven muscles from the upper extremity, trunk and lower extremity regions and was complemented by physiological (heart rate, tidal volume, minute ventilation, oxygen consumption, energy expenditure and breathing frequency) and psychophysical (body discomfort) data. At the completion of all nine conditions subjects completed a retrospective psychophysical rating questionnaire pertaining to discomfort felt during the conditions. Responses obtained for the different task and posture combinations revealed compensatory reactions (additive > combined) for most of the conditions assessed for the biomechanical and physiological responses. In the majority of cases for muscle activity, no significant differences were found between the combined and the additive effects (p < 0.05), while for the physiological responses there were mostly significant differences observed. Psychophysical responses indicated that there was a significant difference overall between the additive and combined effects. The results of this study demonstrate that in order to identify risk areas, manipulation tasks and constrained working postures may be considered either in isolation and added together (additive) or as a combined task, since there were very few significant differences observed between these two effects. Further studies are required, however, to provide conclusive evidence.
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The factors predisposing social workers to burnout in the social services organizations of the Eastern Cape
- Authors: Ramphele, Thamaga Zacharia
- Date: 2005
- Subjects: Burn out (Psychology) , Social workers -- Psychology , Job stress , Social service -- Research , Social workers -- Job stress -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:6059 , http://hdl.handle.net/10962/d1006667 , Burn out (Psychology) , Social workers -- Psychology , Job stress , Social service -- Research , Social workers -- Job stress -- South Africa -- Eastern Cape
- Description: This work was based on an investigation of the subject of burnout, as observed by the researcher among social workers that worked for various social services organizations - both Government Departments and Non-Governmental Organizations - based in the Eastern Cape Province. The study of burnout was conducted with the aim to obtain information from the respondents about their conditions at work, and how those conditions contributed, as alleged, to burnout experienced by them. A qualitative research method was used as an approach that the researcher found best in that it allowed for an in-depth probe into the circumstances of the respondents (including the attitudes and emotions of the respondents), to give a broad picture of the situation as experienced by the respondents at work. A qualitative method was handled through the exploratory research principle of sampling and gathering of data, as the researcher felt it a sufficiently appropriate route to help yield the required outcomes of the study. The researcher's motivation to pursue the research was prompted by several indicators which included an article in the Daily Dispatch of 26 August 2003 that wrote 'Social workers quit in droves' and some personal contact with graduated students of social work, recently employed as social workers in various settings. Interesting dynamics about social work practice and its frustrations surfaced, and out of that premise, the researcher felt that it was an opportune moment to carry out an investigation to discover the facts about burnout as experienced by social workers. The findings on the research would be published, and the researcher intended to inform the social work community about the outcomes of research, hoping that the information would become useful to them in curtailing or preventing future encounters of burnout as experienced by them at the work place. In other words, recommendations for solutions would be provided based on the findings as an outcome of that investigation. To allow for the success of the research process, the researcher planned to draw from several resource centers and other researchers' data, any valuable piece of information, record, or existing data that could assist in evaluating information that became available during data collection. Such information was seen as very important since it helped in making the data analysis process easier and more than enough information could thus be obtained. Finally the researcher had found the study quite fascinating in that it addressed human concerns in the form of social work issues at work, which the researcher personally considered important and shared as one of the issues affecting social work professionals.
- Full Text:
- Authors: Ramphele, Thamaga Zacharia
- Date: 2005
- Subjects: Burn out (Psychology) , Social workers -- Psychology , Job stress , Social service -- Research , Social workers -- Job stress -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:6059 , http://hdl.handle.net/10962/d1006667 , Burn out (Psychology) , Social workers -- Psychology , Job stress , Social service -- Research , Social workers -- Job stress -- South Africa -- Eastern Cape
- Description: This work was based on an investigation of the subject of burnout, as observed by the researcher among social workers that worked for various social services organizations - both Government Departments and Non-Governmental Organizations - based in the Eastern Cape Province. The study of burnout was conducted with the aim to obtain information from the respondents about their conditions at work, and how those conditions contributed, as alleged, to burnout experienced by them. A qualitative research method was used as an approach that the researcher found best in that it allowed for an in-depth probe into the circumstances of the respondents (including the attitudes and emotions of the respondents), to give a broad picture of the situation as experienced by the respondents at work. A qualitative method was handled through the exploratory research principle of sampling and gathering of data, as the researcher felt it a sufficiently appropriate route to help yield the required outcomes of the study. The researcher's motivation to pursue the research was prompted by several indicators which included an article in the Daily Dispatch of 26 August 2003 that wrote 'Social workers quit in droves' and some personal contact with graduated students of social work, recently employed as social workers in various settings. Interesting dynamics about social work practice and its frustrations surfaced, and out of that premise, the researcher felt that it was an opportune moment to carry out an investigation to discover the facts about burnout as experienced by social workers. The findings on the research would be published, and the researcher intended to inform the social work community about the outcomes of research, hoping that the information would become useful to them in curtailing or preventing future encounters of burnout as experienced by them at the work place. In other words, recommendations for solutions would be provided based on the findings as an outcome of that investigation. To allow for the success of the research process, the researcher planned to draw from several resource centers and other researchers' data, any valuable piece of information, record, or existing data that could assist in evaluating information that became available during data collection. Such information was seen as very important since it helped in making the data analysis process easier and more than enough information could thus be obtained. Finally the researcher had found the study quite fascinating in that it addressed human concerns in the form of social work issues at work, which the researcher personally considered important and shared as one of the issues affecting social work professionals.
- Full Text:
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