Relationship Between Lower-Body Power and Sport-Specific Start Performance in International-Level BMX Riders.

Background: Bicycle Motocross (BMX) performance is strongly influenced by the start phase, which requires rapid force and power production to achieve optimal race posi-tioning; however, the relationship between lower-body power and sport-specific start performance remains insufficiently investigated. Objectives: The aim of this cross-sectional study was to assess lower-body muscular performance and analyze its relationship with start performance in international BMX riders. Methods: Ten international-level BMX riders (n = 10) completed a testing battery including squat jump and countermovement jump, force-velocity profile assessment, and a Wingate test preceded by 5 s maximal sprints to determine peak power (PP1, PP2), peak power during the 30 s Wingate test, and mean power. A sport-specific start test was performed on a BMX ramp, with time over the first 15 m recorded using photocell timing gates. Results: StartGate 15 m time showed a large negative correlation with PP2 (r = -0.800, 95% CI: -0.95 to -0.33, p = 0.05), whereas no significant correlations were observed with vertical jump performance or Power Mean Wingate. Strong correlations were observed among laboratory-based power variables. Conclusions: These findings suggest that short-duration peak cycling power may be associated with BMX start performance. However, given the small sample size and the borderline p-value, this relationship should be interpreted with caution. Sport-specific start testing may provide relevant information for performance assessment and training monitoring in international BMX riders.