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
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
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
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
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
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
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 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
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
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 interrelationship of physical fitness, somatotype, body cathexis and personality in a group of white schoolboys
- Authors: Fieldsend, Jeremy Rowell
- Date: 1980
- Subjects: Somatotypes -- Psychological aspects , Physical fitness for children -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5139 , http://hdl.handle.net/10962/d1006343 , Somatotypes -- Psychological aspects , Physical fitness for children -- Psychological aspects
- Description: The evaluation of physical fitness is dependent upon the body and its capacity to generate requisite degrees of strength, speed, mobility and endurance, for effective physical performance. The physical properties of the body, and in particular the degree of muscularity and adiposity, are affected substantially by varying levels of physical fitness. This degree of muscularity and adiposity is closely related to the shape or physique of the body, which in turn, can influence the attitudes an individual adopts toward his body and himself (body cathexis). The purpose of this study was to investigate the reciprocal relationship between physical fitness, somatotype (physique) and body cathexis (satisfaction). A secondary objective was to examine the relationship between these variables and personality. The subjects who participated in this study were white schoolboys completing Standard Eight. Seventy seven subjects, all of whom were either 14 or 15 years of age, were studied. A total of 22 observations were made on each subject, which included a battery of physical fitness tests, anthropometric and somatotypological observations, and two questionnaires. Fleishman's Basic Fitness Test battery, which was slightly modified, was utilized to evaluate the subjects' level of physical fitness. Standardized anthropometric techniques and equipment were used to measure heights, mass, diameters, girths, and skinfolds. These basic anthropometric observations were then utilized to determine the subjects' Heath-Carter somatotype rating, absolute and relative body fat, and lean body mass. Body cathexis was measured by the Secord-Jourard Body Cathexis Scale and personality was assessed by the Howarth personality Questionnaire. The results indicated that physical fitness performance on the events which required the body mass to be displaced were highly and negatively related to the degree of excess adipose tissue. Significant differences in endomorphy (p < 0,005) were apparent in high and low fit groups, but no somatotypological differences were indicated for those events which did not involve the displacement of the body mass. The one exception to this was a static strength event, in which significant somatotypological differences between high and low fit groups were indicated for mesomorphy (p < 0,005) and ectomorphy (p < 0,01). Body cathexis was not closely related to physical fitness, somatotype, or personality. A number of weak relationships were apparent: there was a negative correlation between body cathexis and the personality trait of inferiority; high levels of adipose tissue negatively influenced the level of body cathexis; and good performance on the strength events was positively associated with body cathexis. In the physical fitness events requiring strength and the body mass to be displaced, the body cathexis levels of high fit subjects exceeded that of low fit subjects at a statistically significant level (p < 0,005). No significant differences in body cathexis were indicated for those events which did not require the displacement of the body mass. Personality was not related to physical fitness, somatotype or body cathexis. The only relationship that was discerned was the low correlation between inferiority and body cathexis . The findings of this investigation suggest that, in this context, dynamic physical fitness performance, is closely related to physique; and in particular a high endomorphic content is a limiting factor. Body cathexis is not closely related to physical fitness, somatotype or personality. It is likely, however, that feelings of inferiority and excess adipose tissue are associated with a low body cathexis, while strength is related to a high body cathexis. Personality is not related to physical fitness, physique or body.
- Full Text:
- Date Issued: 1980
- Authors: Fieldsend, Jeremy Rowell
- Date: 1980
- Subjects: Somatotypes -- Psychological aspects , Physical fitness for children -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5139 , http://hdl.handle.net/10962/d1006343 , Somatotypes -- Psychological aspects , Physical fitness for children -- Psychological aspects
- Description: The evaluation of physical fitness is dependent upon the body and its capacity to generate requisite degrees of strength, speed, mobility and endurance, for effective physical performance. The physical properties of the body, and in particular the degree of muscularity and adiposity, are affected substantially by varying levels of physical fitness. This degree of muscularity and adiposity is closely related to the shape or physique of the body, which in turn, can influence the attitudes an individual adopts toward his body and himself (body cathexis). The purpose of this study was to investigate the reciprocal relationship between physical fitness, somatotype (physique) and body cathexis (satisfaction). A secondary objective was to examine the relationship between these variables and personality. The subjects who participated in this study were white schoolboys completing Standard Eight. Seventy seven subjects, all of whom were either 14 or 15 years of age, were studied. A total of 22 observations were made on each subject, which included a battery of physical fitness tests, anthropometric and somatotypological observations, and two questionnaires. Fleishman's Basic Fitness Test battery, which was slightly modified, was utilized to evaluate the subjects' level of physical fitness. Standardized anthropometric techniques and equipment were used to measure heights, mass, diameters, girths, and skinfolds. These basic anthropometric observations were then utilized to determine the subjects' Heath-Carter somatotype rating, absolute and relative body fat, and lean body mass. Body cathexis was measured by the Secord-Jourard Body Cathexis Scale and personality was assessed by the Howarth personality Questionnaire. The results indicated that physical fitness performance on the events which required the body mass to be displaced were highly and negatively related to the degree of excess adipose tissue. Significant differences in endomorphy (p < 0,005) were apparent in high and low fit groups, but no somatotypological differences were indicated for those events which did not involve the displacement of the body mass. The one exception to this was a static strength event, in which significant somatotypological differences between high and low fit groups were indicated for mesomorphy (p < 0,005) and ectomorphy (p < 0,01). Body cathexis was not closely related to physical fitness, somatotype, or personality. A number of weak relationships were apparent: there was a negative correlation between body cathexis and the personality trait of inferiority; high levels of adipose tissue negatively influenced the level of body cathexis; and good performance on the strength events was positively associated with body cathexis. In the physical fitness events requiring strength and the body mass to be displaced, the body cathexis levels of high fit subjects exceeded that of low fit subjects at a statistically significant level (p < 0,005). No significant differences in body cathexis were indicated for those events which did not require the displacement of the body mass. Personality was not related to physical fitness, somatotype or body cathexis. The only relationship that was discerned was the low correlation between inferiority and body cathexis . The findings of this investigation suggest that, in this context, dynamic physical fitness performance, is closely related to physique; and in particular a high endomorphic content is a limiting factor. Body cathexis is not closely related to physical fitness, somatotype or personality. It is likely, however, that feelings of inferiority and excess adipose tissue are associated with a low body cathexis, while strength is related to a high body cathexis. Personality is not related to physical fitness, physique or body.
- Full Text:
- Date Issued: 1980
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
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