Thesis (MAppSc in Physiotherapy) -- University of South Australia, 1998

Thesis (MAppSc) -- University of South Australia, 1997

Copies of author's previously published articles inserted at back / Bibliography: leaves 211-220 / viii, 220 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Summary: Investigates various problems relating to scoliosis and manual load handling. Introduces the idea of deducing optimal load lifting techniques which take into into account multiple joint/muscle complexes / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied Mathematics, 1994

Thesis (Ph. D.)--University of Adelaide, Dept. of Applied Mathematics, 1994. / Copies of author's previously published articles inserted at back. Includes bibliographical references (leaves 211-220).

Dissertation (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (p.94-106).

Thesis (M.S.)--Central Connecticut State University, 1997. / Thesis advisor: Dr. Robert Trichka. " ... in partial fulfillment of the requirements for the degree of Master of Science in Physical Education." Includes bibliographical references (leaves 162-169).

Thesis (M.Sc. (Human Kinetics & Ergonomics)) - Rhodes University, 2009.

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains x, 92 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 81-82).

Two hypotheses were formulated to examine the additivity of perceived exertion in repetitive, symmetric, mid-sagittal lifting. "Additivity" has been defined as the means by which a whole-body rating of perceived exertion is composed of a weighted combination of component ratings of perceived exertion. The "task additivity" hypothesis asserts that a perceived exertion rating for the whole body in a floor-to-overhead lifting task can be modelled by the perceived exertion ratings of the component motions, i.e., floor-to-knuckle height lifting and knuckle height-to-overhead lifting. This is an inter-task (subtask) additivity paradigm. The "body-segment additivity" hypothesis asserts that the perceived exertion rating for the whole body in a floor-to-overhead lifting task can be modelled by a combination of the ratings of perceived effort from the arms, legs, torso, and central (cardio-respiratory) body functions. This is an intra-task (regional) additivity paradigm. / Master of Science

Although much effort has been placed into the reduction of risks associated with manual materials handling, risk of musculoskeletal disorder development remains high. This may be due to the additional muscle activity necessary for the maintenance of postural equilibrium during work tasks. This research proposes that postural control and subsequent additional muscle activity is influenced by the magnitude of the external load and the degree of body movement. The objective of this research was to identify whether performing tasks with increased external load and with a greater degree of trunk motion places additional strain on the musculoskeletal system in excess of that imposed by task demands. Twenty-four male and twenty-four female subjects performed four load manipulation tasks under three loading conditions (0.8kg, 1.6kg, and 4kg). Each task comprised of a static and dynamic condition. For the static condition, subjects maintained a stipulated posture for ten seconds. The dynamic condition required subjects to move and replace a box once every three seconds, such that a complete lift and lower cycle was performed in six seconds. Throughout task completion, muscle activity of six pairs of trunk muscles were analysed using surface electromyography. This was accompanied by data regarding ground reaction forces obtained through the use of a force platform. After the completion of each condition subjects were required to identify and rate body discomfort. Differential analysis was used to isolate the muscle activity and ground reaction forces attributed to increased external load and increased trunk movement. It was found that the heaviest loading conditions (4kg) resulted in significantly greater (p<0.05) muscle activation in the majority of muscles during all tasks investigated. The trend of muscle activity attributed to load was similar in all significantly altered muscles and activation was greatest in the heaviest loading condition. A degree of movement efficiency occurred in some muscles when manipulating loads of 0.8kg and 1.6kg. At greater loads, this did not occur suggesting that heavier loading conditions result in additional strain on the body in excess of that imposed by task demands. In manipulated data, trend of vertical ground reaction forces increased with increased load in all tasks. Sagittal movement of the centre of pressure attributed to load was significantly affected in manipulated data in the second movement phase of the “hip shoulder” task and the second movement phase of the “hip twist” task. The “hip reach” task was most affected by increased load magnitude as muscle activity attributed to load was significantly different (p<0.05) under increased loading conditions in both movement phases in all muscles. Further, a significant interactional effect (p<0.05) between condition and data point was found in all muscles with the exception of the right and left lumbar erector spinae during the second movement phase of the “hip reach” task. Muscle activity associated with increased trunk motion resulted in additional strain on the trunk muscles in the “hip shoulder” and “hip reach” tasks as muscle activity associated with the static component of each of the above tasks was greater than that of the dynamic tasks. Trend of ground reaction forces attributed to increased trunk motion generally increased under increased loading conditions. Additionally, a significant interactional effect (p<0.05) between load and muscle activity pattern was found in all muscles during all tasks, with the exception of the right rectus abdominis in the first movement phase of the “hip shoulder’ task, the left rectus abdominis in the second movement phase of the “hip knee” task and the right latissimus dorsi during the first movement phase of the “hip twist” task. This was accompanied by a significant interactional effect (p<0.05) between load and sagittal centre of pressure movement attributed to load, in both movement phases of all tasks investigated. From this research it can be proposed that guidelines may underestimate risk and subsequently under predict the strain in tasks performed with greater external loads as well as tasks which require a greater degree of trunk motion. Therefore, this study illustrates the importance of the consideration of the muscle activity necessary to maintain postural equilibrium in overall load analyses.