Chiu Loren Z F, Dæhlin Torstein E, Jean Liane M Y, Fielding Zachary A
Neuromusculoskeletal Mechanics Research Program, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada.
Neuromusculoskeletal Mechanics Research Program, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB T6G 2H9, Canada.
J Biomech. 2022 Mar;134:110998. doi: 10.1016/j.jbiomech.2022.110998. Epub 2022 Feb 14.
The ankle plantar flexor muscles are stronger in ankle dorsiflexion than plantar flexion. However, heel lift is commonly observed during ankle plantar flexor strength testing, a phenomenon that would alter ankle angle. The effect of heel lift on the relation between ankle angle and plantar flexor strength has largely been ignored. This research examined the ankle plantar flexor strength curve, correcting for ankle plantar flexion due to heel lift. Six males and six females performed maximal isometric ankle plantar flexor contractions at five ankle positions. The purpose-built dynamometer could measure both resting ankle angle and foot plantar flexion due to heel lift; the combination was used to calculate the ankle angle during contraction. A significant interaction between dynamometer position and heel lift correction was observed (P < 0.001). The interaction had a linear trend (adjusted R = 0.94, P < 0.001) indicating heel lift was smallest in ankle plantar flexion and increased with greater ankle dorsiflexion. The difference in ankle angle following heel lift correction occurred with the ankle in dorsiflexion (P < 0.001, Cohen's d = 2.6) and near neutral (P < 0.001, Cohen's d = 2.2). After correcting for heel lift, the ankle plantar flexor strength curve was compressed to a smaller range of ankle angles, specifically, reducing the maximum dorsiflexion angle.
踝关节跖屈肌在踝关节背屈时比跖屈时更强壮。然而，在踝关节跖屈肌力量测试中通常会观察到足跟抬起的现象，这一现象会改变踝关节角度。足跟抬起对踝关节角度与跖屈肌力量之间关系的影响在很大程度上被忽视了。本研究检测了踝关节跖屈肌力量曲线，并对由于足跟抬起导致的踝关节跖屈进行了校正。六名男性和六名女性在五个踝关节位置进行了最大等长踝关节跖屈收缩。特制的测力计可以测量静息踝关节角度以及由于足跟抬起导致的足部跖屈；二者结合起来用于计算收缩过程中的踝关节角度。观察到测力计位置与足跟抬起校正之间存在显著的交互作用（P < 0.001）。该交互作用呈线性趋势（调整后R = 0.94，P < 0.001），表明足跟抬起在踝关节跖屈时最小，并随着踝关节背屈程度的增加而增大。足跟抬起校正后踝关节角度的差异出现在踝关节背屈时（P < 0.001，科恩d值 = 2.6）和接近中立位时（P < 0.001，科恩d值 = 2.2）。校正足跟抬起后，踝关节跖屈肌力量曲线被压缩到更小的踝关节角度范围，具体而言，最大背屈角度减小。
