Biomechanical analysis of hammer throwing: assessment of speed development

Other Publication ResearchOnline@JCU
Brice, Sara Michelle
Abstract

The aim of the hammer throw is to project the hammer as far as possible and, major contributing factor to throw success is the speed of the hammer at the instant of release. The thrower accelerates the hammer to the instant of release by performing turns across the hammer throw circle, during which time the hammer's linear speed fluctuates. The first two studies of this thesis were concerned with ascertaining how an athlete could improve speed development in the hammer throw while the third study was focused on development and validation of a system that would facilitate direct measurement of speed development in the training environment. Study one focused on assessing the relationship between the hammer's linear speed and the thrower applied cable force. This was done to identify how cable force magnitude and direction affects the speed development, specifically losses. Speed losses occur when the tangential component of the cable force (tangential force) is negative. The loss of speed caused by the negative tangential force can be reduced in two ways: by decreasing the magnitude of the negative tangential force itself or by decreasing the amount time that it acts for. Results of this study indicate that it is more effective for a thrower to decrease the magnitude of the negative tangential force. Throwers can do this by reducing either the cable force magnitude or by the angle between the cable force and linear hammer velocity. The findings presented here indicate that the most effective way to minimise the impact of negative tangential force is to reduce the angle. Study two was concerned with identifying how a thrower could alter their technique so as to lead to a reduction in the size of losses in speed. In this study, the relationship between speed losses and movement of the throwers thorax relative to the pelvis (thorax-pelvis separation angle) was investigated. The results of this study indicate that throwers should aim to reduce the size of the thorax-pelvis separation angle during double support, specifically during turn two and the second last turn. This was found to result in a smaller loss in speed during the subsequent single support phase. The aim of study three was to develop and validate a method that would facilitate accurate feedback of linear hammer speed within the training environment as this would allow athletes and coaches to implement the technique changes outlined in study two and assess how these changes affect hammer speed. The most accurate way to determine hammer speed is via hammer three-dimensional position data; however, current methods of collecting these data do not allow provision of immediate feedback. In this study, a method that would allow speed to be determined from cable force information was sought as methods that allow immediate feedback on cable force data have already been validated.

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185

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DOI

10.25903/k26s-3042