The relationship braking-phase metrics have with jump height and strategy during the countermovement jump with arm swing

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 the relationships between braking-phase measures and jump height during a CMJ with arm swing and identify whether distinct braking-phase strategies are adopted. Fifty-one team-sport athletes (30 male, 21 female) performed three maximal CMJ trials using motion capture and force plate analysis. Associations with jump height during CMJ with arm swing were assessed using correlation coefficients and linear regression, while principal component analysis (PCA) and k -means clustering were adopted to identify different movement strategies. 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. The present study indicates potential relationships between braking-phase measures and jump height during the CMJ with arm swing. This research can also potentially aid in the identification of specific CMJ strategies, suggesting that individuals may be distinguished by their lower-limb joint flexion rates and the magnitude of braking peak power production relative to body mass. Not applicable.