Aim: The aim of the present study was to assess the validity of jump height (h), absolute (VPOWERABS) and relative to body mass (VPOWERREL) performance indices when elicited of a modified 30 s Bosco vertical jump test (VJT) based on the absolute (WPOWERABS) and relative (WPOWERREL) power values of a 30 s Wingate test (WAnT).
Methods: Nineteen physical education students with mean ± SD age 21 ± 3 y, body mass 73.8 ± 7 kg and height 1.8 ± 0.06 m performed a 30 s VJT on a force plate and a 30 s WAnT on a Monark cycle ergometer. Performance data were expressed in W and W.kg-1 of body mass for WPOWERABS and WPOWERREL; in cm, W and W.kg-1 for h, VPOWERABS and VPOWERREL, respectively. The performance indices' values were expressed as means and SDs of the 30 s duration of both tests, as well as in 4 time intervals of 7.5 s (0-7.5 s, 7.5-15 s, 15-22.5 s, and 22.5-30 s).
Results: WPOWERABS and h were significantly (P<0.05) correlated in the 4 time intervals (0-7.5 s: r=0.51; 7.5-15 s: r=0.36; 15-22.5 s: r=0.39) and in the overall duration of the test (0-30 s: r=0.38). Significant correlation was also revealed between VPOWERABS and WPOWERABS, but only for the interval 0-7.5 s (r=0.48).
Conclusion: A 30 s VJT is valid against a 30 s WAnT only when h is used as performance indices. The selection of the appropriate unit of measurement is important for assessing effort distribution in maximum effort tests of short duration.