Data from: Operating length and velocity of human M. vastus lateralis fascicles during vertical jumping

Humans achieve greater jump height during a counter movement jump (CMJ) than in squat jump (SJ). However, the crucial difference is the mean mechanical power output during the propulsion phase, which could be determined by intrinsic neuro-muscular mechanisms for power production. We measured M. vastus lateralis (VL) fascicle length changes and activation patterns and assessed the force-length, force-velocity and power-velocity potentials during the jumps. Compared to the SJ, the VL fascicles operated on a more favourable portion of the force-length curve (7% greater force potential) and more disadvantageous portion of the force-velocity curve (11% lower force potential) in the CMJ, indicating a reciprocal effect of force-length and force-velocity potentials for force generation. The higher muscle activation (15%) could therefore explain the moderately greater jump height (5%) in the CMJ. The mean fascicle shortening velocity in the CMJ was closer to the plateau of the power-velocity curve, which resulted in a greater power-velocity potential (15%). Our findings provide evidence for a cumulative effect of three different mechanisms - i.e. greater force-length potential, greater power-velocity potential and greater muscle activity - for an advantaged power production in the CMJ contributing to the marked difference in mean mechanical power (57%) compared to SJ.