Fukuyama Hiroshi, Maeo Sumiaki, Kusagawa Yuki, Isaka Tadao
Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, Japan.
Graduate School of Sport and Health Science, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, 525-8577, Shiga, Japan.
Sci Rep. 2025 May 23;15(1):17948. doi: 10.1038/s41598-025-02917-9.
During tiptoe standing, especially with the single-legged support, the foot joints in ballet dancers are heavily loaded. Thus, the activity of the plantar intrinsic foot muscles (PIFMs), which stabilize the foot joints, may be important in reducing postural sway during tiptoe standing. We compared PIFM activity during single-legged and bipedal tiptoe standing and examined its relationship to postural sway in dancers. In 11 female ballet dancers, the electromyography (EMG) amplitudes of PIFMs and the center of pressure (COP) data were recorded during single-legged and bipedal tiptoe standing tasks. The EMG amplitudes were normalized to those during the maximal voluntary contraction, and PIFM activity level and its coefficient of variation over time (EMG-CV) during the task were assessed. From the COP data, standard deviations in the anteroposterior (COP-SD) and mediolateral (COP-SD) direction, velocity, and area were calculated. PIFM activity level and COP velocity were 2-2.5-fold higher in the single-legged than bipedal task (p ≤ 0.003). Significant correlations were found between PIFM activity level and COP velocity (r = 0.666, p = 0.025) and between EMG-CV and COP-SD or COP-SD (r ≥ 0.738, p ≤ 0.010) only in the single-legged task. These results suggest that PIFM activity is associated with postural sway, especially during single-legged tiptoe standing in dancers.
在踮脚尖站立时，尤其是单腿支撑时，芭蕾舞演员的足部关节承受着巨大的负荷。因此，稳定足部关节的足底固有足部肌肉（PIFMs）的活动，对于减少踮脚尖站立时的姿势晃动可能很重要。我们比较了单腿和双腿踮脚尖站立时PIFMs的活动情况，并研究了其与舞者姿势晃动的关系。在11名女性芭蕾舞演员中，记录了她们在单腿和双腿踮脚尖站立任务期间PIFMs的肌电图（EMG）幅度以及压力中心（COP）数据。将EMG幅度标准化为最大自主收缩时的幅度，并评估任务期间PIFM的活动水平及其随时间的变异系数（EMG-CV）。根据COP数据，计算前后方向（COP-SD）和内外侧方向（COP-SD）的标准差、速度和面积。单腿任务中PIFM的活动水平和COP速度比双腿任务高2-2.5倍（p≤0.003）。仅在单腿任务中，发现PIFM活动水平与COP速度之间存在显著相关性（r=0.666，p=0.025），以及EMG-CV与COP-SD或COP-SD之间存在显著相关性（r≥0.738，p≤0.010）。这些结果表明，PIFM活动与姿势晃动有关，尤其是在舞者单腿踮脚尖站立时。
