Browsing by Author "Bridger, Robert S"

Now showing 1 - 4 of 4
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    Anthropometric variability, equipment usability and musculoskeletal pain in a group of nurses in the Western Cape
    (1997) Botha, Winifred Edna; Bridger, Robert S; Morris, Alan
    This study examined the anthropometry and anthropometric fit of a group of ward and theatre nurses in Western Cape private hospitals. Anthropometric variables were measured using a sample of nurses and a correlation matrix generated. All nurses were given a questionnaire concerned with operational problems in the work environment and musculoskeletal pain. The questionnaire was also completed by a group of sedentary nurses. The ward and theatre nurses reported numerous problems in the working environment, including lumbar backache, inadequate space and equipment that caused bodily discomfort. There were consistent, statistically significant associations between the frequency of occurrence of these problems and the anthropometric data indicating that the problems were caused or amplified by body size variability and were not simply general usability problems which would affect all nurses irrespective of their body dimensions. Further studies testing specifically for the consequences of mismatches and body size variability are recommended.
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    The effectiveness of ergonomic training on visual display terminal operators
    (2000) Stern, Vivienne Ruth; Davidson, Tony; Bridger, Robert S
    This study was conducted in order to evaluate the effectiveness of a "self-help" ergonomics-training program, which was instituted in order to reduce the risk of musculoskeletal disorders and eyestrain in video display terminal (VDT) operators.
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    Interrelationships between spinal and pelvic angles and hip muscle indices and their implications for workspace design
    (1991) Bridger, Robert S
    The shape of the lumbar and thoracic spinal curves in healthy subjects, when standing and when adopting a variety of working positions, was investigated using angular measures. The hypothesis that spinal and pelvic posture is determined by body position was supported. The mechanism by which body position influences spinal and pelvic posture was investigated using angular indices of the lengths of the hip flexors and extensors. The hypothesis that hamstring stretch determines postural adaptation to sitting positions was not supported. A multivariate analysis revealed that an index of iliopsoas length was the best predictor of posterior pelvic tilt in a variety of sitting positions. A supplementary investigation was carried out using data on the range of motion of the pelvis in the different body positions and its relationship to the muscle length indices. The role of the hamstring muscles in sitting posture was clarified. Some electromyographic data is presented to further illustrate the effect of body position on the role of the hip and trunk muscles in posture. A replication of the main findings and an investigation of some of the practical implications of the work were carried out drawing attention to some mechanisms of postural stress, potential problems of increased lumbar lordosis and their cost-effective alleviation through workspace design. The provision of a footrest, for example, was found to have significant effects on lumbar and pelvic angles in standing as well as in sitting. Further research into standing posture in the workplace is indicated by these findings. Some hypotheses for future investigation are presented.
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    An investigation of the ergonomics and biomechanics of rifle shooting from the standing position
    (1991) Smith, Jan Ryno; Bridger, Robert S
    The purpose of this study was to investigate the ergonomics and biomechanics of rifle shooting from the standing position. At present, the scientific literature on shooting contains primarily qualitative descriptions of the various aspects of the sport. Quantitative data on the kinetic and kinematic aspects of standing rifle shooting was collected in the present thesis. Transducers were developed to measure foot forces in the vertical and horizontal plane, recoil force on the shoulder and the grip force of the trigger hand. Kinematic data was collected with a video camera. The study revealed that recoil energy was dependent on the attributes of the shooter. Handgrip forces were found to be well below the maximum handgrip strength. An exploratory investigation of the interrelationships among foot forces, rifle recoil and angular and linear displacements was carried out. No horizontal foot forces to counteract the recoil force were observed. A possible explanation for the finding is proposed. The findings are discussed with reference to the ergonomic implications for rifle stock design. Further investigations of the relationships between shooting performance and the man-rifle interface are indicated.