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Jump evaluation of elite volleyball players using two methods: jump power equations and force platform.

BACKGROUND
The aim of the present study was to determine the best jump power equation in the evaluation of elite volleyball players using both the force platform and peak power equations.


METHODS
Nine elite volleyball players and nine sedentary subjects performed counter-movement jump tests on a force platform.


RESULTS
Peak power and height were greater in the volleyball players than in the sedentary subjects, whatever the method used. The results demonstrated that the peak power values obtained on the force platform and those scored from the equations of Lewis, Harman and Sayers et al. were correlated when the whole sample was taken into account. However, a significant equation x level interaction (p<10(-4)) indicated different behaviour as a function of performance level. In sedentary subjects, peak power was significantly underestimated using the Lewis equation (943+/-162 W; p<10(-4)) and did not differ using both the Harman (3004+/-563 W) and Sayers (3400+/-604 W) equations when compared to the peak power noted with the force platform (3372+/-532 W). In contrast, in volleyball players, peak power was underestimated using the three equations (1246+/-78 W, p<10(-4); 4314+/-216 W, p<0.001; 4607+/-251, p<0.005; for the Lewis, Harman and Sayers equations, respectively, versus 5355+/-522 W for the force platform).


CONCLUSIONS
The results of the present study demonstrate the difficulty in choosing the most relevant equation in the jump power calculation.