The relationship countermovement jump braking-phase metrics have with jump height and strategy: A cross-sectional study

Background The countermovement jump (CMJ) is the most common jumping variation seen in jumping-based sports and physical assessment batteries. Current evidence indicates large heterogeneity in the influence of braking-phase metrics on CMJ performance, with recent literature suggesting there may be unique braking-phase movement strategies that exist. This investigation aimed to determine how braking-phase measures affect CMJ height and identify whether distinct braking-phase strategies are adopted in trained team-sport athletes. Methods Fifty-one team-sport athletes (30 male, 21 female) performed three maximal CMJ trials using motion capture and force deck analysis. Associations with CMJ height were assessed using correlation coefficients and linear regression, while principal component analysis (PCA) and k -means clustering were adopted to identify different movement strategies. Results Twenty-three significant correlations were observed for the group ( p  < 0.05), with weak to very strong relationships, twelve (52%) of which were braking-phase measures. Knee flexion peak velocity, braking peak power relative to body mass, hip flexion acceleration, and time to peak ankle dorsiflexion were the braking-phase measures retained for the final regression model. Two clusters were identified and could primarily be distinguished by PC1 (hip flex accel, knee flex accel, time to peak knee flex, time to peak hip flex, and relative braking PP), accounting for 41.61% of the group variance. Conclusions Consideration should be made towards individualising training interventions, match play tactics, return-to-play criteria, and biomechanical frameworks based on movement strategy to enhance individual athlete outcomes. Trial registration : Not applicable.