Year: 2003
Type: dissertation
Abstract: Running jumps such as the high jump and the long jump involve complex\nmovements of the human body. The factors affecting performance include\napproach conditions, strength of the athlete and the muscle activation timings at\neach joint. In order to investigate the mechanics of jumping performances and the\neffect of these factors, an eight-segment, subject specific, torque-driven computer\nsimulation model of running jumps was developed, evaluated and used to optimise\nperformances of jumps for height and distance.\nWobbling masses within the shank, thigh and trunk segments, and the\nground-foot interface were modelled as non-linear spring-damper systems. The\nvalues for the stiffness and damping constants were determined through\noptimisation. The inertia data were obtained from anthropometric measurements\non the subject using the inertia model of Yeadon (1990b). Joint torques predicted\nby the simulation model were expressed as a function of angular velocity and\nangle using data collected from an isovelocity dynamometer. The simulation\nmodel was evaluated by comparing the actual performances with simulations\nusing kinematic and kinetic data collected.\nMovement of the wobbling masses was found to be in the region of 40 mm\nin the shank and thigh and 90 mm in the trunk. This movement resulted in a\nlower, more realistic initial peak in the ground reaction force. Co-contraction was\nfound to occur at the joints during impact in order to increase the initial level of\neccentric activation and also the rise time to maximum eccentric activation.\nDifferences of 2% and 1% in the height and distance achieved were obtained\nbetween actual performances and simulations.\nAn optimisation procedure was used to maximise the height reached and\ndistance travelled by the mass centre, in simulations of jumps for height and\ndistance respectively, by varying the torque generator activation time histories at\neach joint. An increase of 12% in the height reached by the mass centre in the\njump for height and 14% in the distance reached by the mass centre in the jump\nfor distance were achieved.
Author: Cassie Wilson
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W157920061