Mechanical power distribution of the lower limbs changed during intermittent 300 countermovement jumps.

Abstract

Purpose: The aim of this study was to investigate the effect of 300 intermittent countermovement jumps (CMJs) on the mechanical power distribution at the joints of the lower limbs and the influence of the upper body to explain vertical jump performance.

Methods: Fifteen male sport students (age 24.5 ± 2.3 years; body height 1.85 ± 0.06 m; body mass 84.8 ± 8.5 kg) performed a set of intermittent 300 CMJs at maximal effort. An inverse-dynamic approach was used to calculate the mechanical power at the hip, knee, and ankle joint for each jump.

Results: Jump height and mechanical power in the knee and ankle joints decreased significantly (p < .010), while remained the same in the hip joint. In contrast, a significant increased vertical velocity was observed for the upper body segment. In addition, a significant higher angular momentum at the center of mass was detected during the braking and propulsion phase.

Conclusion: The findings highlight a fatigue-related decrease in lower limb power, particularly in the knee and ankle joints, which changed the mechanical power distribution at the joints of the lower limbs. The trunk extensor muscles were probably able to counteract the fatigue-related decrease in lower limb power by increased vertical velocity of the upper body segment and higher angular momentum at the center of mass during the braking and propulsion phase. Accordingly, the most effective way to maintain jumping performance in fatigued state would be to improve the fatigue resistance of the knee extensors, ankle plantar flexors, and trunk extensor muscles.