Kean Crystal O, Hinman Rana S, Wrigley Tim V, Lim Boon-Whatt, Bennell Kim L
School of Health, Medical, and Applied Sciences, Central Queensland University, Rockhampton, QLD, Australia.
Centre for Health, Exercise and Sports Medicine (CHESM), Department of Physiotherapy, The University of Melbourne, Victoria, Australia.
Clin Biomech (Bristol). 2017 Feb;42:20-24. doi: 10.1016/j.clinbiomech.2017.01.002. Epub 2017 Jan 4.
Greater impact loading at initial contact is postulated to play a role in the progression of osteoarthritis. Quadriceps weakness is common in individuals with knee osteoarthritis and may contribute to high impact loading. The purpose of this study was to examine the effects of quadriceps strengthening on impact loading parameters.
Data from 97 individuals with knee osteoarthritis who participated in a randomized clinical trial examining effects of a 12-week quadriceps strengthening program was used to conduct this secondary exploratory analysis. Participants completed a three-dimensional gait assessment within 10% of 1.0m/s from which maximum rate of loading (Body Weight/second), average rate of loading (Body Weight/second), and peak vertical ground reaction force during early stance (Body Weight) were determined. Peak isometric quadriceps strength (Nm/kg) was also assessed.
There was a significant increase in quadriceps strength in the training group (mean change (95%CI): 0.35(0.25, 0.045) Nm/kg, P=0.01) with no change in the control group (mean change (95%CI): 0.03(-0.39, 0.45) Nm/kg, P>0.05). There were no changes in impact loading variables. With data from both groups combined, changes in quadriceps strength explained 3% of variance in the change in maximum rate of loading. Change in quadriceps strength was not predictive of the change in peak vertical ground reaction force or average rate of loading.
While change in strength was predictive of change in maximal loading rate, this explained only a small proportion of the variance. Future research examining the role parameters such as neuromuscular control play in impact loading are warranted.
据推测，初始接触时更大的冲击负荷在骨关节炎的进展中起作用。股四头肌无力在膝关节骨关节炎患者中很常见，可能导致高冲击负荷。本研究的目的是检查股四头肌强化训练对冲击负荷参数的影响。
本二次探索性分析使用了97名膝关节骨关节炎患者的数据，这些患者参与了一项随机临床试验，该试验研究了为期12周的股四头肌强化训练计划的效果。参与者在速度为1.0m/s的10%范围内完成三维步态评估，由此确定最大负荷率（体重/秒）、平均负荷率（体重/秒）以及早期站立时的垂直地面反作用力峰值（体重）。还评估了股四头肌等长力量峰值（牛顿米/千克）。
训练组的股四头肌力量显著增加（平均变化（95%置信区间）：0.35（0.25，0.45）牛顿米/千克，P = 0.01），而对照组没有变化（平均变化（95%置信区间）：0.03（-0.39，0.45）牛顿米/千克，P>0.05）。冲击负荷变量没有变化。将两组数据合并后，股四头肌力量的变化解释了最大负荷率变化中3%的方差。股四头肌力量的变化不能预测垂直地面反作用力峰值或平均负荷率的变化。
虽然力量变化可预测最大负荷率的变化，但这仅解释了一小部分方差。有必要开展未来研究，探讨神经肌肉控制等参数在冲击负荷中的作用。
