Kinematic Analysis of Synchronized Skaters During the Off‐Ice Execution of Spiral and Spin Tasks

The primary objective of the present study was to examine differences and associations in joint angles and segmental swings during the off-ice execution of one static (spiral) and one dynamic (spin) sport-specific balance task and to determine whether motor control strategies differ when participants perform the tasks on their dominant and nondominant legs. Junior synchronized skaters (n = 15, age = 16.3 ± 1.5 years, years of practice: 9.8 ± 2.8 years, 10 females) performed spiral and spin tasks three times with 60 s of rest allowed between each trial. Participants' movements were captured using an optical-based motion capture (MoCap) system that utilized 39 skin-attached retro-reflective markers. Our results indicate no differences in synchronized skaters' kinematic features when the spiral task is performed on their dominant versus nondominant leg (p > 0.05). However, the results of Spearman's correlation analyses suggest different motor control strategies between the various body segments during right- versus left-leg task execution. In addition, participants produced a larger swing with their left versus right arm, regardless of whether the spiral task was performed on the dominant (39.97 ± 10.32 vs. 30.22 ± 7.80, p < 0.001) or the nondominant (52.88 ± 13.65 vs. 37.12 ± 9.59, p < 0.001) leg. Lastly, the association between the knee angle of the supporting leg and the swing of the head (ρ = -0.54; p = 0.038) suggests that the greater the knee angle of the support leg during the spins, the less compensatory head swing was needed during the task.