LONG JUMP: MECHANICAL AND ENERGETIC ASPECTS

Abstract

The use of variation techniques is applied to investigate jumper's posture at take-off, resulting in maximum distance of jump. Explicit expressions have been derived between: (i) the take-off angle ϕT (formed by the line connecting the contact point of the leg driving the jump with the ground to the centre of mass position and the horizontal), (ii) the ratio [Formula: see text] of the mean vertical component of the ground reaction force vector to athlete's weight at take-off, (iii) the time spent for the mid-support/take-off phase TT, and (iv) the change in the vertical component of the displacement of the centre of mass compared with the take-off foot ΔyT, measured between two extreme postures, i.e. the mid-support and the take-off phase. The method is illustrated by calculating the state vector [Formula: see text] at take-off, in connection with the take-off angle ϕT. The results are compared to direct measurements from real long jumps.