Kinetic characteristics of Wushu Changbing PiJi: decoupling sex-specific adaptive strategies via functional principal...

Wushu Changbing PiJi is a representative striking action in Wushu long-weapon routines, with its most iconic form derived from the Ma's Tongbei Wushu school, whose staff techniques represent a direct lineage of the Ming Dynasty Shaolin staff system. Biomechanically, it is a high-velocity, long-lever striking action analogous to other open-chain striking tasks. However, sex-specific ground reaction force (GRF) control and force transmission strategies during this movement remain unclear.

This study aimed to characterize sex-specific kinetic adaptations during Wushu Changbing PiJi using multivariate functional principal component analysis (mfPCA) of three-dimensional ground reaction forces (3D GRFs).

Fifty elite collegiate Wushu Changbing athletes performed maximal-effort PiJi trials with synchronized optical motion capture and dual force plates. mfPCA was used to extract the core spatiotemporal modes of normalized 3D GRFs. Linear mixed-effects models were then applied to test sex effects on five principal component scores and 16 discrete kinetic metrics.

No significant sex differences were observed in PC1, PC2, or PC5, indicating a shared core spatiotemporal kinetic structure across sexes. In contrast, significant sex effects were found in PC3 and PC4, reflecting differences in fine-grained control strategies.Males demonstrated greater total peak implement kinetic energy, alongside increased peak lateral force, mean propulsive force, and lateral force standard deviation, consistent with a propulsion-dominant but less stable kinetic profile. Females showed higher PC3 and vertical impulse, suggesting a control-oriented braking and stabilization strategy.

Wushu Changbing PiJi appears to be governed by a shared core force-generation rhythm, while sex-specific adaptations are primarily expressed through a propulsion-stability trade-off. These findings support sex-specific training interventions that preserve the common temporal template while targeting stability control in males and power-conversion capacity in females.