Countermovement rebound jump: a comparison of joint work and joint contribution to the countermovement and drop jump tests

The kinetic analysis of joint work and joint contribution provides practitioners with information regarding movement characteristics and strategies of any jump test that is undertaken. This study aimed to compare joint works and contributions, and performance metrics in the countermovement jump (CMJ), drop jump (DJ), and countermovement rebound jump CMRJ. Thirty-three participants completed 18 jumps across two testing sessions. Jump height and strategy-based metrics (time to take-off [TTTO], countermovement depth [CM depth], and ground contact time [GCT]) were measured. Two-way analysis of variance assessed systematic bias between jump types and test sessions (α = 0.05). Reliability was evaluated via intraclass correlation coefficient [ICC] and coefficient of variation [CV]. Jump height and strategy-based metrics demonstrated good to excellent reliability (ICC = 0.82–0.98) with moderate CV (≤8.64%). Kinetic variables exhibited moderate to excellent reliability (ICC = 0.64–0.93) with poor to moderate CV (≤25.04%). Moreover, apart from TTTO (p ≤ 0.027, effect size [ES] = 0.49–0.62) that revealed significant differences between jump types, CM depth (p ≤ 0.304, ES = 0.27–0.32) and GCT (p ≤ 0.324, ES = 0.24) revealed nonsignificant trivial to small differences between three jumps in both sessions. Finally, the negative and positive hip and knee works, and positive ankle contribution measured in the CMRJ showed significant differences from the CMJ and DJ (p ≤ 0.048, g ≤ 0.71), with no significant difference observed in other kinetic variables between the three jump actions (p ≥ 0.086). Given the consistent joint works and joint contributions between jump types, the findings suggest that practitioners can utilize the CMRJ as a viable alternative to CMJ and DJ tests, and the CMRJ test offers valuable insights into movement characteristics and training suggestions.

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