Zhang Xini, Deng Liqin, Yang Yang, Xiao Songlin, Li Lu, Fu Weijie
School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China.
School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; Institute of Sport and Sport Science, University of Freiburg, Schwarzwaldstraße 175, 79117 Freiburg, Germany.
J Biomech. 2021 Nov 9;128:110807. doi: 10.1016/j.jbiomech.2021.110807. Epub 2021 Oct 9.
Minimalist shod runners have reported greater material and mechanical properties of the Achilles tendon (AT) due to increased loading than runners who wear more cushioned running shoes. This study aimed to investigate the effects of 12-week transition training from conventional shoes to minimalist shoes on AT loading in habitual rearfoot strike runners. Seventeen healthy male habitual rearfoot strikers completed 12-week transition training. They were instructed either to run in minimalist shoes with a forefoot strike pattern (MIN + FFS, n = 9) or run in minimalist shoes but were free to develop their strike pattern (MIN, n = 8). Ultrasound images were captured to determine the cross-sectional area of the AT. Sagittal plane ankle kinematics and ground reaction forces were recorded simultaneously to quantify ankle joint mechanics and AT loading. The strike angle significantly decreased in MIN + FFS after the transition training, indicating a flatter foot at initial contact, whereas no changes were observed in MIN. After training, a significant increase in peak plantarflexion moment was observed for MIN + FFS (15.4%) and MIN (7.6%). Significantly increased peak AT force, peak loading rate and peak stress were observed after training in both groups. Specifically, MIN + FFS had a greater increase in peak AT force (20.3% versus 10.1%), peak loading rate (37.2% versus 25.4%) and peak AT stress (13.7% versus 8.1%) than MIN. Furthermore, for both groups, there were no significant differences in the moment arm and cross-sectional area of the AT observed before and after 12 weeks of training. The results of this study suggested that it was insufficient to promote the morphological adaptation of the AT, but the mechanical loading of the AT was adapted during running after 12-week transition training with minimalist shoes in MIN + FFS and MIN. Preliminary evidence showed that a gradual transition to minimalist shoes with a forefoot strike pattern may be beneficial to the mechanical loading of the AT.
与穿着更具缓冲性跑鞋的跑步者相比，穿极简主义跑鞋的跑步者报告称，由于负荷增加，跟腱（AT）的材料和力学性能更佳。本研究旨在调查习惯后足着地跑步者从传统鞋子过渡到极简主义鞋子进行12周训练对跟腱负荷的影响。17名健康的男性习惯后足着地跑步者完成了12周的过渡训练。他们被指示要么穿着极简主义跑鞋采用前足着地模式跑步（MIN + FFS，n = 9），要么穿着极简主义跑鞋跑步，但可自由形成自己的着地模式（MIN，n = 8）。采集超声图像以确定跟腱的横截面积。同时记录矢状面踝关节运动学和地面反作用力，以量化踝关节力学和跟腱负荷。过渡训练后，MIN + FFS组的着地角度显著降低，表明初始接触时足部更扁平，而MIN组未观察到变化。训练后，MIN + FFS组（15.4%）和MIN组（7.6%）的跖屈力矩峰值均显著增加。两组训练后均观察到跟腱力峰值、负荷率峰值和应力峰值显著增加。具体而言，MIN + FFS组的跟腱力峰值（20.3%对10.1%）、负荷率峰值（37.2%对25.4%）和跟腱应力峰值（13.7%对8.1%）的增加幅度均大于MIN组。此外，两组在训练12周前后观察到的跟腱力臂和横截面积均无显著差异。本研究结果表明，12周的极简主义跑鞋过渡训练不足以促进跟腱的形态适应，但在MIN + FFS组和MIN组中，跟腱的机械负荷在跑步过程中得到了适应。初步证据表明，逐渐过渡到采用前足着地模式的极简主义跑鞋可能有利于跟腱的机械负荷。
