Objectives: Although the overuse injury rate of the Achilles tendon (AT) for running is high, the effect of shoe conditions on AT loading remains unclear. Hence, this study aims to determine the mechanical properties of AT during running under different shoe conditions (minimalist vs. conventional shoes).

Design:This work is a controlled laboratory study.

Methods:Sixteen healthy male rearfoot strike runners were recruited to complete over ground running trials at 3.33 m/s (±5%) under two shoe conditions (minimalist shoes: INOV-8 Bare-XF 210; conventional shoes: NIKE AIR ZOOM PEGASUS 34). Sagittal plane ankle kinematics and ground reaction forces were simultaneously recorded. Ankle joint mechanics (ankle joint angle and moment) and the mechanical properties (peak force, impulse, stress, strain, and their corresponding peak rate) of the AT were calculated.

Results: In comparison with conventional shoes, wearing minimalist shoes showed significant changes (p < 0.05): (1) decreased strike angle (48.92 ± 9.01 vs. 41.04 ± 8.69°); (2) increased ankle moment (2.34 ± 0.44 vs. 2.55 ± 0.46 Nm/kg); (3) increased peak AT force (5.85 ± 1.22 vs. 6.24 ± 1.13 BW), AT force impulse (0.65 ± 0.13 vs. 0.70 ± 0.13 BW·s), peak AT loading rate (109.94 ± 9.33 vs. 118.84 ± 26.62 BW/s), and average loading rate (48.42 ± 15.64 vs. 54.90 ± 17.47 BW/s); (4) decreased time to peak AT force (126.31 ± 20.68 vs. 117.77 ± 17.62 ms); (5) increased AT stress (66.96 ± 14.59 vs. 71.89 ± 14.74 MPa), strain (8.19 ± 1.77 vs. 8.78 ± 1.80 %), peak AT stress rate (66.96 ± 14.59 vs. 71.89 ± 14.74 MPa/s), and strain rate (148.71 ± 48.52 vs. 167.28 ± 42.82 %/s).

Conclusion: Increased AT force, loading rate, and stress were observed in runners who habitually wear conventional shoes with rearfoot strike patterns when they wore minimalist shoes. Hence, we recommend a gradual transition to minimalist shoes for runners who habitually wear conventional shoes with rearfoot strike patterns.

目的：尽管跟腱过度磨损对跑步的伤害率很高，但鞋子状况对AT负荷的影响尚不清楚。因此，本研究旨在确定AT在不同鞋子条件下（极简主义鞋与传统鞋）的机械性能。

设计：这项工作是对照实验室研究。

方法：招募了16名健康的男性后足罢工跑步者，以在两种鞋子条件下（极简主义鞋子：INOV-8 Bare-XF 210；常规鞋子：NIKE AIR ZOOM PEGASUS 34）以3.33 m / s（±5％）的速度完成地面跑步试验）。同时记录矢状面踝运动学和地面反作用力。计算了AT的踝关节力学（踝关节角度和力矩）和机械性能（峰值力，冲量，应力，应变及其相应的峰值速率）。

结果：与传统鞋相比，穿极简主义鞋表现出显着变化（p <0.05）：（1）打击角减小（48.92±9.01 vs. 41.04±8.69°）；（2）脚踝力矩增加（2.34±0.44 vs. 2.55±0.46 Nm / kg）；（3）增加了峰值AT力（5.85±1.22 vs. 6.24±1.13 BW），AT力脉冲（0.65±0.13 vs. 0.70±0.13 BW·s），峰值AT加载速率（109.94±9.33 vs. 118.84±26.62 BW / s），以及平均负载率（48.42±15.64 vs. 54.90±17.47 BW / s）；（4）达到最大AT力的时间减少了（126.31±20.68 vs. 117.77±17.62 ms）；（5）AT应力增加（66.96±14.59 vs. 71.89±14.74 MPa），应变（8.19±1.77 vs. 8.78±1.80％），峰值AT应力率（66.96±14.59 vs.71.89±14.74 MPa / s）和应变率（148.71±48.52 vs. 167.28±42.82％/ s）。

结论：习惯穿传统鞋后脚罢工的跑步者在穿着极简主义鞋时观察到AT力，负重率和压力增加。因此，我们建议逐渐习惯极简主义的鞋子，适合惯于穿着具有后脚罢工模式的传统鞋子的跑步者。