THE EFFECT OF lWO FORCE SLEDGE APPARATUS JUMPING PROTOCOLS ON TRIAL TO TRIAL RELIABILITY AND MUSCLE PERFORMANCE

This experiment examined the effect of differing jump protocols performed on a specially constructed force sledge apparatus on trial to trial reliability and overall lower extremity muscular performance. Eight adult volunteers, of varying activity profiles, participated in this study. On the force sledge apparatus, subjects performed bouts of drop jumps and rebound jumps. Measurements of flight time, ground contact time, reactive strength index, peak ground reaction force, displacement of spring mass and vertical stiffness were obtained for three drop jumps and three rebound jumps on the sUbjects' preferred jumping leg. The results indicated that the rebound jump protocol provided a tighter control of ground contact times and displacement of spring mass, indicatin9' a more consistent jumping strategy. Additionally, a significantly higher peak ground reaction force was produced in the rebound jump protocol.