不同分级神经肌肉疲劳对冲击性落地动作下肢生物力学的非线性影响

The Non-linear Effect of Neuromuscular Fatigue on the Biomechanics of Lower Extremities during Landing

目的:考察随神经肌肉疲劳程度的进展,运动员在冲击性落地动作中下肢生物力学的变化,以探讨由于疲劳所引起的膝关节前交叉韧带(ACL)等损伤的可能性机制。方法:9名女性篮球运动员通过变向跑和连续纵跳来获得下肢神经肌肉疲劳,疲劳进展的等级划分为无疲劳、中度疲劳、重度疲劳。在每个等级下,实验人员采集受试者落地动作中的运动学和动力学数据并进行统计分析。结果:与无疲劳相比,达到中度疲劳等级后落地过程中落地时间显著延长(P=0.004),膝关节刚度显著降低(P=0.046),髋(P=0.040)、膝(P=0.001)、踝(P<0.001)三个关节的屈曲角度峰值显著增大,髋关节伸力矩(P=0.007)和地面反作用力(P=0.002)峰值显著减小;与中度疲劳相比,达到重度疲劳等级后膝关节刚度显著增大(P=0.048),髋关节伸力矩(P=0.012)和地面反作用力峰值(P=0.017)显著增大。结论:疲劳对落地过程中下肢生物力学参数产生了显著的非线性影响。随着疲劳的加深,落地策略的变化呈现由"硬着陆"到"软着陆"再到"硬着陆"的变化趋势.重度疲劳可能导致ACL等组织受到的被动载荷增加,导致其潜在性损伤风险增大。

Objective This study aimed to investigate the biomechanical changes in lower extremities of basketball players during landing as progressing of muscular fatigue in order to explain the possible mechanism of ACL injury.Methods Neuromuscular fatigue of lower extremity in 9 female basketball players was developed through varying direction running and continuous vertical jumping.Neuromuscular fatigue were classified as stages of no fatigue,moderate fatigue and severe fatigue.At the different stages,the subjects received landing tests and the kinematic and kinetic data were simultaneously recorded and analyzed.Results Compared to the no fatigue stage,there were prolonged landing time（P =0.004）.weakened knee stiffness（P = 0.046）.larger flexions of hip（P = 0.040）,knee（P = 0.001） and ankle（P 0.001）.smaller hip extension moment（P = 0.007） and ground reaction force（P = 0.002）during landing at the moderate fatigue stage.Compared to the moderate fatigue stage,there were greater knee stiffness（P = 0.048）.greater hip extension moments（P = 0.012）,and greater ground reaction forces（P = 0.017） during landing at the severe fatigue stage.Conclusions There were non-linear effects of various levels of neuromuscular fatigue on the biomechanics of lower extremity.Severe neuromuscular fatigue could probably lead to increase the risk of ACL injury.