Statistical Parametric Mapping reveals sex-specific, phase-dependent differences in bilateral three-dimensional ground reaction force during Wushu Changbing PiJi in high-level athletes
Jinyong Feng, Lianzhen Ma, Yupeng Shen, Shuxin Wang, Yiyi Qiu, Pengfei Zheng
PiJi is a core attacking technique in Wushu Changbing competition, but continuous waveform evidence remains limited regarding the sex-specific phase characteristics of bilateral 3D ground reaction force (GRF) during PiJi performed with maximal voluntary effort (MVE). This study aimed to compare continuous changes in trailing-foot, lead-foot, and net bilateral GRF between high-level male and female athletes during PiJi performed with MVE. In this cross-sectional, laboratory-based observational study, 44 right-hand-dominant athletes, including 22 male athletes and 22 female athletes, performed PiJi with MVE, yielding 616 valid trials. Bilateral 3D GRF was recorded using two force plates. Each trial was time-normalized and linearly interpolated to 143 equally spaced nodes, and within-participant mean waveforms were calculated before between-group differences were analyzed using statistical parametric mapping. Primary analyses used random-field-theory inference, with sensitivity examined using 5,000 permutation tests. After Bonferroni correction, phase-specific sex differences were detected in trailing-foot, lead-foot, and net bilateral 3D GRF. Scalar localization showed that male athletes had higher trailing-foot