A Vertical Jump Force Test for Assessing Bilateral Strength Asymmetry in Athletes.

Impellizzeri, Franco; Rampinini, Ermanno; Maffiuletti, Nicola; Marcora, Samuele.

The purpose of this study was to establish the validity and reliability of a new vertical jump force test (VJFT) for the assessment of bilateral strength asymmetry in a total of 451 athletes.  The VJFT consists of countermovement jumps with both legs simultaneously: one on a single force platform, the other on a leveled wooden platform. Jumps with the right or the left leg on the force platform were alternated and bilateral strength asymmetry were calculated. The correlation between the VJFT and other tests of lower-limb bilateral strength asymmetry, VJFT reliability, the effect of rehabilitation on bilateral strength asymmetry after unilateral knee surgery and normative data were determined and are described.  The authors conclude that the assessment of bilateral strength asymmetry with the VJFT is valid and reliable, and it may be useful in sports medicine.

Medicine & Science in Sports & Exercise, 2007,    39(11), 2044-2050

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