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Shot put biomechanics: Study of the individual technique model

Abstract:

This paper describes biomechanical analysis of 11 valid throws of the Spanish record-breaker Manuel Martínez in 3 Spanish Championships from 1996 to 1998. The aim of these studies was to describe the individual technique as much as identify the cinematic variables that more correlated with the distance of throw. Possible technique improvements are investigated as well as dependence between variables with multiple regression. Two synchronised video cameras at 50 Hz with PAL/ SECAM video system were used to film the throws. One camera was placed in rear position and the other in the lateral right (except in the first Championship that it was placed on the left) according to the circle of throw. 26 points human model apart from one point for the shot was used to digitise. One cubic calibration frame (2 m per side) was filmed before and after the competitions. Spatial reconstruction was made using Kinescan 8.0 IBV software, which uses DLT algorithms. The studied technique model stands out for not having transition phase and for it's high stability (few variations in the 11 studied throws). Sliding distance was 0.75±0.07 m, during this phase the shot covers horizontally 1.43±0.08 m over the 2.26±0.08 m that it covers on the hole throw before the release. The lower limbs movement goes on according to the technique so called "short-long". The variables with best R2 with the distance thrown are the horizontal and vertical distance covered by the shot, the twist of the feet, and the variation of the left knee angle, all of them in the last phase. From an isolated point of view neither the angle of release nor the height of release show correlation with the distance of throw, but with the velocity of release altogether they show R2 =0.995.