Core activation patterns across different figure skating jumps

This study presents a quantitative analysis of core muscle activation patterns across six distinct figure skating jumps: single/double axel, double/triple salchow, and double/triple loop. While previous research has focused primarily on lower-limb kinematics, the role of the trunk in maintaining a rigid rotational axis remains underexplored. We utilized a synchronized sensor framework comprising torso-mounted accelerometers, bilateral electromyography (EMG) of the m. obliquus externus abdominis and m. rectus abdominis, and skate-mounted inertial measurement units to monitor 12 adolescent female athletes. The EMG signals were segmented into the preparation, flight, and landing phases and subsequently normalized to the percentage of inter-trial maximum (%ITM). Our findings reveal a consistent shift from right-side dominance during the preparation phase to left-side dominance during the flight phase (for counter-clockwise rotators). Triple jumps exhibited higher integrated ITM in the obliquus externus compared to double jumps, despite minimal differences in airtime. This suggests that increased rotational velocity ( ≈ 1570 °/s) necessitates higher muscular tension rather than a longer duration in the air. Furthermore, the landing phase was characterized by a powerful bracing mechanism, with the co-contraction index exceeding 80% in high-rotation jumps. This study provides an objective framework for evaluating jump technique and optimizing strength training in competitive figure skating.