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Biomechanics of the lower extremities in the shot put linear technique of the finalists of the Spanish athletics championship of San Sebastian '98

Abstract:

An aspect frequently studied in Biomechanics is the performance of the shot-putters' lower extremities. On performing the put, two tendencies were defined in the linear technique, the 'short-long' and the 'long-short' executions. They were described according to the value of the distance covered by the right foot in its initial stage of the flight, 'glide phase', and the distance between the feet in 'power position'. Using the three- dimensional video technique, different variables of the feet movement were studied through a cinematic analysis of the best eight puts with linear technique performed in the Outdoors Absolute Spanish Championship held in San Sebastian in 1998. The puts were manually digitized reconstructing the three- dimensional co-ordinates with the DLT algorithm and using five order spline functions for smoothing. Three-dimensional animations of the lower extremities were made so as to obtain a better understanding of the movement and an independent display of them. The 'short-long' tendency was proved to be the prevailing one with a mean glide of 0.960±0.160 m and with a distance between the toes in 'power position' of 1.574±0.122 m. During the initial phase the right foot is resting on the ground and in the subsequent flight, in the 'glide phase', this segment performed a anticlockwise spin which oriented it towards the X-axis 120±114.6°. According to the authors' considerations, the width of the angle should be 90°, however, it is also pointed out that in the 'short-long' technique, it is not very important to place the right foot so turned on the centre of the circle. Moreover the left lower extremity was observed to perform an anticlockwise rotation on the fore part of the foot of 30.3±15.7°in its last stage of support before the release. It is worth pointing out how, at the moment of release, all the analysed shot-putters lost contact with the ground, which different authors see as a negative aspect, although it is quite frequent. In the studied puts, the biomechanics of the lower extremities agrees with the ideal technical model of the glide technique, which is indicative of the high technical level of the Spanish shot-putters.