A biomechanical analysis of the last stride, touch-down and take-off characteristics of the women's long jump.

This study was concerned with the measurement of a selection of performance variables from competitors in the women's long jump final of the World Student Games held in Sheffield, UK in July 1991. Several performances of each of six finalists were recorded on cine-film at 100 Hz. Resulting planar kinematic data were obtained for the last stride, touch-down and take-off. For the analysis, the point of maximum knee flexion was established and this was used to represent the point at which the compression phase had ended. A variety of variables describing the position, velocity and angular changes are presented as descriptive data. In addition, these were used to compute energies on the basis of a whole body model. The data were interpreted on the basis of a technique model of long jumping established from the literature. It was confirmed that take-off velocity was a function of touch-down velocity, and that there was an increase in vertical velocity at the expense of a reduction of horizontal velocity. An attempt was made to identify the mechanisms acting during the touch-down to take-off phase which were responsible for generating vertical velocity. It was concluded that there was evidence for mechanical, biomechanical and muscular mechanisms. The former relates to the generation of vertical velocity by the body riding over the base of support; the second is the elastic re-utilization of energy; and the third is the contribution by concentric muscular contraction.