Risk assessment and the effects of overhead work - an automotive industry example
- Authors: Elliott, Andrew Brent
- Date: 2008
- Subjects: Human engineering -- South Africa , Industrial safety -- South Africa , Automobile industry workers -- South Africa -- Health risk assessment , Automobile industry and trade -- South Africa -- Safety measures , Musculoskeletal system -- Wounds and injuries -- Prevention , Lifting and carrying -- Safety measures , Work measurement , Posture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5132 , http://hdl.handle.net/10962/d1005211 , Human engineering -- South Africa , Industrial safety -- South Africa , Automobile industry workers -- South Africa -- Health risk assessment , Automobile industry and trade -- South Africa -- Safety measures , Musculoskeletal system -- Wounds and injuries -- Prevention , Lifting and carrying -- Safety measures , Work measurement , Posture
- Description: The focus of this investigation was an analysis of the work demands being placed on South African automotive industry workers as there is a recognised problem with regard to the prevalence of musculoskeletal disorders (MSDs). Preliminary work was conducted to highlight the dominant risks and areas which elicited higher numbers of MSDs within the chosen automotive plant. An area of concern was highlighted through medical record analysis and the use of risk assessment tools, thereby prioritising the need for ergonomic intervention. In particular, the effects of varying restricted and overhead work heights on the biomechanical, physiological and psychophysical responses of an individual were investigated. Twenty-eight subjects were required to complete sixteen conditions. The conditions consisted of the adoption of restricted and upright overhead static postures, with half requiring the holding of four kilograms of weight in the hands and the remaining eight conditions having no weight. Testing was carried out using an electromyography unit, ergospirometer and a perceptual Body Discomfort Map and Scale. This involved a habituation and testing session. The results of the testing revealed the biomechanical and physiological responses were dependant on the change in height. Body discomfort was also shown to be variable over the changing height conditions. This indicates that there is a significant effect of height on an individual’s responses during overhead work. The extreme restricted (-200mm and -100mm) and upright (+300mm and +400mm) overhead conditions within this study were limiting, as they elicited the highest muscle activation, physiological responses and body discomfort ratings. Positions that are preferable to adopt, which were identified from the results in this study, indicate conditions closer to head height (0mm and +100mm) were favourable. The results therefore illustrate how awkward working postures during work are likely to elicit higher demands from an individual, which could lead to an increased risk for the development of a musculoskeletal disorder. The added factor of weight elicited significant results over all variables, excluding a respiratory The focus of this investigation was an analysis of the work demands being placed on South African automotive industry workers as there is a recognised problem with regard to the prevalence of musculoskeletal disorders (MSDs). Preliminary work was conducted to highlight the dominant risks and areas which elicited higher numbers of MSDs within the chosen automotive plant. An area of concern was highlighted through medical record analysis and the use of risk assessment tools, thereby prioritising the need for ergonomic intervention. In particular, the effects of varying restricted and overhead work heights on the biomechanical, physiological and psychophysical responses of an individual were investigated. Twenty-eight subjects were required to complete sixteen conditions. The conditions consisted of the adoption of restricted and upright overhead static postures, with half requiring the holding of four kilograms of weight in the hands and the remaining eight conditions having no weight. Testing was carried out using an electromyography unit, ergospirometer and a perceptual Body Discomfort Map and Scale. This involved a habituation and testing session. The results of the testing revealed the biomechanical and physiological responses were dependant on the change in height. Body discomfort was also shown to be variable over the changing height conditions. This indicates that there is a significant effect of height on an individual’s responses during overhead work. The extreme restricted (-200mm and -100mm) and upright (+300mm and +400mm) overhead conditions within this study were limiting, as they elicited the highest muscle activation, physiological responses and body discomfort ratings. Positions that are preferable to adopt, which were identified from the results in this study, indicate conditions closer to head height (0mm and +100mm) were favourable. The results therefore illustrate how awkward working postures during work are likely to elicit higher demands from an individual, which could lead to an increased risk for the development of a musculoskeletal disorder. The added factor of weight elicited significant results over all variables, excluding a respiratory individual.
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- Date Issued: 2008
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.
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- Date Issued: 1986