Effects of Static, Countermovement, and Drop Jump Performance on Power and Rate of Force Development in 6 - 16 Year Old Boys

The purpose of this study was to examine the effects of static, counter movement, and drop jump performance on peak power and peak rate of force development (RFD). The secondary purpose of this study was to examine the relationship between vertical jump outcomes, maturity offset, and muscle cress-sectional area (CSA). During a single testing session, twenty-one young males (mean age ± SD = 12.1 ± 2.4 yrs) performed maximal vertical jumps which included: static jump (SJ), counter movement jump (CMJ), and drop jump from 8 (DJ8), 12 (DJ12) and 16 (DJ16) inches in a randomized order. Peak power increased from SJ to CMJ (p ≤ 0.001) but showed no subsequent increases among CMJ, DJ8, DJ12, or DJ16. RFD and force showed no increase from SJ to CMJ (p \u3e 0.05), an increase from CMJ to DJ8 (p ≤ 0.001), but no further increases from DJ8 to DJ12 to DJ16 (p \u3e 0.05). Eccentric impulse increased systematically from SJ to DJ16 (p ≤ 0.001). Concentric impulse increased from SJ to CMJ (p ≤ 0.001), decreased from CMJ to DJ8 (p = 0.003), then showed no change from DJ8 to DJ12 to DJ16 (p \u3e 0.05). Stepwise regression indicated that the increase in power from SJ to CMJ was best explained by height (R2 = 0.517). These findings suggest CMJ is the optimal jump test for maximizing peak power and concentric work, while minimizing eccentric overload in male of a similar age to this study. Additionally, growth and development may influence stretch-shortening cycle (SSC) utilization. Future studies are needed to examine the influence of PHV maturity offset and increased muscle CSA on SSC utilization in this model of incremental eccentric pre-loading during vertical jump tests. Advisor: Joel T. Crame