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Direct measurement of power with jump tests in female volleyball

Abstract:

Mechanical power in jump tests can be directly measured by a force platform, or estimated (indirect way) from a subject's jump height and body mass, by means of different equations (Lewis, Harman and Sayers). The aim of this study was to evaluate, directly and indirectly, peak power from lower extremities using jump tests in a club level female volleyball team (n = 13). A secondary purpose was to compare if one method is more suitable than the others. Subjects performed three different jump tests, on a force platform: Abalakov (ABK), countermovement jump (CMJ) and squat jump (SJ). Peak power in ABK was 3536 ± 631 W (force platform); 839 ± 120 W (Lewis) and 2834 ± 542 W (Harman). Peak power in CMJ was 2856 ± 554 W (force platform); 760 ± 110 W (Lewis); 2408 ± 465 W (Harman) and 2703 ± 450 W (Sayers), and for the SJ, peak power was 2878 ± 538 W (force platform); 677 ± 106 W (Lewis); 1996 ± 428 W (Harman) and 2310 ± 459 W (Sayers). The force platform is the more accurate instrument to measure mechanical power in jump tests. The Lewis equation underestimated peak power (p<0,01). The Harman equation also underestimated peak power, but less than Lewis equation (p<0,01). The Sayers equation gave measures closer to those taken from the force platform, although they have been significantly different, as well (p<0,01). In conclusion, the better way to evaluate power would be directly, using a force platform. The Sayers equation seems to give power measures closer to those obtained by direct methods.