Relationships between jumping asymmetry and performance in skateboarders

The influence of asymmetry on performance in sports with highly asymmetric demands is yet to be properly determined. This investigation sought to examine jump-based asymmetries within skateboarders and determine any possible relationships with subjective skating ranking and jumping performance. Twelve recreational skateboarders (age: 24 ± 7 years; height: 1.76 ± 0.12 m; body mass: 66.7 ± 39.2 kg) volunteered to participate in the study. All participants had at least ten years of skateboarding experience. Participants completed one familiarisation trial followed by a single experimental trial. In the experimental trial, skaters performed three trials of three different unilateral jump tests (squat jump [SJ], countermovement jump [CMJ] and drop jump [DJ]) following a standardised dynamic warm-up. Jump heights and DJ reactive strength index (RSI) were determined via the MyJump2 smartphone application. Large asymmetries were reported across all jump tests. However, effect sizes suggested a smaller magnitude of asymmetry for CMJ height (13.6%) versus SJ height (20.5%; d = 0.66) and DJ height (20.2%; d = 0.50). A large positive correlation was reported between SJ asymmetry and subjective ranking (ρ = 0.60; P = 0.04), such that skaters with larger asymmetries ranked higher. However, SJ asymmetry was associated with a lower DJ RSI (ρ = -0.68; P = 0.01). No asymmetries were associated with CMJ height which has been previously liked to Ollie performance in skateboarders. These data suggest that asymmetries are highly prevalent in experienced recreational skateboard athletes but are not associated with skating performance.