Influence of ethnicity on vertical jump performances in male physical education students: a pilot study

The present study aimed to: 1) test the possibility of ethnic differences in squat jump (SJ), countermovement jump (CMJ) and countermovement jump with arms swing (CMJA); 2) test the possibility of ethnic differences in the effects of countermovement and arms swing; 3) verify whether the relationships between the different vertical jumps (VJ) (SJ, CMJ, CMJA) and maximal power (Pmax), determined from a force-velocity test (F-V), were dependent on the ethnicity as previously found for CMJA.

VJ were performed by 84 active men (WAC): 40 WA and 44 C. VJ were measured on a force platform in three conditions: SJ, CMJ and CMJA. For technical reasons, only 39 of these participants (WA2C2) performed F-V test [V=V0(1-F/F0) and maximal power=0.25 V0F0]: 20 WA (WA2) and 19 C (C2).

There were significant ethnic differences (WA>C) in SJ, CMJ, CMJA, CMJA-CMJ, CMJA/CMJ. The effect sizes (Cohen d) of these ethnic differences were large for CMJA (0.93), CMJA-CMJ (1.11) CMJA/CMJ (0.82) and medium for CMJ (0.54) and SJ (0.56). Ethnic effect in the countermovement jump was small (Cohen d=0.04 for CMJ-SJ) and not significant.

For WA2C2, the slightly higher value of Pmax in WA2 (Cohen d =0.23) probably explained their slightly higher values of SJ, CMJ but not their higher values of CMJA and arms swing effect. In WA2C2, a difference in fast-fiber percentages was not the explanation of the ethnic differences because the optimal pedal rates corresponding to Pmax (0.5 V0) were similar in both groups.