Shanghai University of Sport
目的 探讨神经-肌肉疲劳前后缓冲型运动鞋对落地动作下肢冲击力特征以及运动学和动力学的影响。方法 比较15名篮球专项运动员在疲劳干预前后，穿不同缓冲性能的运动鞋从60cm高落地时的冲击力、负载率、下肢运动学、关节力矩、关节/下肢刚度等。结果 疲劳前：高缓冲鞋仅使后跟处负载率峰值减小（389.67 vs. 688.03 BW·s-1），且到达后跟负载率时间比对照组更短（29.9 vs. 36.63 ms）。疲劳后：1）高缓冲鞋显著减小了后跟处冲击力峰值（3.77 vs. 4.5 BW）、负载率峰值（375.51 vs. 756.8 BW·s-1）和前脚掌的负载率峰值（193.17 vs. 265.05 BW·s-1），同时显著延长了到达冲击力（前掌：12.77 vs. 10.07 ms，后跟：41.56 vs. 35.46 ms）和后跟负载率峰值的时间（36.41 vs. 29.9 ms）；2）穿高缓冲鞋使得踝关节触地角度（131.69° vs. 126.51°）、最小角度显著增大（86.97° vs. 84.72°）；3）：在下肢刚度、踝关节峰值力矩和刚度方面两组鞋并未发现显著性的改变。结论 在神经—肌肉疲劳前，高缓冲运动鞋的减震作用并不明显，而在疲劳后高缓冲鞋的减震作用突出，表现在减小了前掌及后跟的冲击力和负载率等，提示：在疲劳后，当人体下肢神经-肌肉控制策略受影响时，高缓冲鞋能够有效地衰减冲击，进而有利于避免/减小潜在的冲击性运动损伤。
Objective The purpose of this study was to examine the effect of shoe cushioning on impact characteristics and kinematics of lower extremities under fatigue conditions during drop landings. Methods Fifteen trained male athletes were required to execute three successful trials of drop landings from a 60-cm platform before and after fatigue protocol. The variables included impact force, loading rate, lower extremity kinematics, joint mechanics, stiffness in the sagittal plane movement. Results Highly-cushioned shoe reduced the loading rate at heel in pre-fatigue (389.67 vs 688.03 BW·s-1), and the time to peak loading rate of heel was significantly shorter than control shoes (29.9 vs 36.63 ms). In post-fatigue: 1) the peak impact force (3.77 vs 4.5 BW) and loading rate at heel (375.51 vs 756.8 BW·s-1), loading rate at forefoot (193.17 vs 265.05 BW·s-1) were significantly reduced of highly-cushioned shoe. Meanwhile the time to peak impact force (forefoot: 12.77 vs 10.07 ms, heel: 41.56 vs 35.46 ms) and peak loading rate of heel (36.41 vs 29.9 ms) were significantly longer of highly-cushioned shoe. 2) Besides, the contact (131.69° vs. 126.51°) and minimum angle (86.97° vs. 84.72°) of ankle were significantly greater of highly-cushioned shoe. 3) No significant changes were found in lower extremity stiffness, peak moment and joint stiffness of ankle. Conclusion Shoe cushioning only make a limited contribution to reducing impact forces before fatigue, while wearing a highly-cushioned shoe can significantly reduce the peak impact force and loading rate during landing in post fatigue. It suggested that in the situation where neuromuscular activity is reduced or absent, highly-cushioned shoe can effectively attenuate the impact, thereby helping to avoid/reduce the potential impact damage after fatigue.