Force-velocity and power-velocity relationships observed from loaded vertical jumps
Date
2015
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Publisher
University of Delaware
Abstract
The aims of the present study were to (1) explore the pattern of force-velocity (F-V ) relationship of leg muscles, (2) evaluate the reliability and concurrent validity of the obtained parameters, and (3) explore the load associated changes in the muscle work and power output. Subjects performed maximum vertical countermovement jumps with a vest ranging 0- 52% of their body mass. The ground reaction force and leg joints kinematics and kinetics were recorded. The data revealed a strong and approximately linear F-V relationship (individual correlation coefficients ranged from 0.69- 0.93). The relationship slopes, F - and V- intercepts, and the calculated power were moderately-to-highly reliable (0.67 < ICC < 0.91), while their concurrent validity with respect to the directly measured values was on average moderate. Despite a load associated decrease in both the countermovement depth and absolute power, the absolute work done increased, as well as the relative contribution of the knee work and power as compared with the hip and ankle. Therefore, the loaded vertical jumps could be developed into a routine method for testing the mechanical properties of leg muscles, while the load associated changes in both the absolute and individual joints' work and power could reveal the mechanisms of adaptation of multi-joint movements to different loading conditions.