Abstract：
BACKGROUND: Muscle weakness is characteristic of knee osteoarthritis. Muscle steadiness may be an important adjunct to knee muscle strength in improving physical function in knee osteoarthritis. However, the role of muscle steadiness is uncertain.
OBJECTIVE: To determine the associations of knee extensor muscle steadiness with maximal voluntary torque and physical function in patients with knee osteoarthritis.
METHODS: Baseline data from 177 patients in a randomized clinical trial were used. Isokinetic knee extension torque was processed into maximal voluntary torque [Nm]. Muscle steadiness was expressed as the coefficient of variance [%] and as peak power frequency [Hz]. Physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index, the Get-Up-and-Go and Stair-climb tests. Associations were determined using regression analyses and adjusted for confounders.
RESULTS: Lower muscle steadiness (i.e., higher coefficient of variance and peak power frequency) was associated with lower maximal voluntary torque (B = - 7.38, [-10.8, -3.95], R2 = 0.10 and B = -14.71, [-28.29, -1.13], R2 = 0.03, respectively). Higher coefficient of variance was associated with lower self-reported physical function (B = 1.14, [0.11,2.17], R2 = 0.03) and remained significant after adjusting for potential confounders. Peak power frequency was not associated with physical function.
CONCLUSIONS: Low muscle steadiness was weakly associated with low muscle strength and poorer self-reported physical function. Muscle steadiness and muscle strength seem to be different attributes of muscle function. There is no convincing evidence that muscle steadiness is an important adjunct in studying physical function in patients with knee osteoarthritis.
OBJECTIVE: To determine the associations of knee extensor muscle steadiness with maximal voluntary torque and physical function in patients with knee osteoarthritis.
METHODS: Baseline data from 177 patients in a randomized clinical trial were used. Isokinetic knee extension torque was processed into maximal voluntary torque [Nm]. Muscle steadiness was expressed as the coefficient of variance [%] and as peak power frequency [Hz]. Physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index, the Get-Up-and-Go and Stair-climb tests. Associations were determined using regression analyses and adjusted for confounders.
RESULTS: Lower muscle steadiness (i.e., higher coefficient of variance and peak power frequency) was associated with lower maximal voluntary torque (B = - 7.38, [-10.8, -3.95], R2 = 0.10 and B = -14.71, [-28.29, -1.13], R2 = 0.03, respectively). Higher coefficient of variance was associated with lower self-reported physical function (B = 1.14, [0.11,2.17], R2 = 0.03) and remained significant after adjusting for potential confounders. Peak power frequency was not associated with physical function.
CONCLUSIONS: Low muscle steadiness was weakly associated with low muscle strength and poorer self-reported physical function. Muscle steadiness and muscle strength seem to be different attributes of muscle function. There is no convincing evidence that muscle steadiness is an important adjunct in studying physical function in patients with knee osteoarthritis.
摘要：
背景：肌无力是膝骨关节炎的特征。在改善膝骨关节炎的身体功能方面，肌肉稳定可能是膝关节肌肉力量的重要辅助手段。然而,肌肉稳定的作用是不确定的。
目的：确定膝关节骨性关节炎患者膝关节伸肌稳定性与最大自主扭矩和身体功能的关系。
方法：使用来自177名随机临床试验患者的基线数据。等速膝关节伸展扭矩被处理为最大自愿扭矩[Nm]。肌肉稳定性表示为变异系数[%]和峰值功率频率[Hz]。使用西安大略省和麦克马斯特大学骨关节炎指数评估身体功能，上上下下和爬楼梯测试。使用回归分析确定关联，并针对混杂因素进行校正。
结果：较低的肌肉稳定性(即，较高的变异系数和峰值功率频率)与较低的最大主动转矩(B=-7.38，[-10.8，-3.95]，R2=0.10，B=-14.71，[-28.29，-1.13]，R2分别=0.03)。较高的变异系数与较低的自我报告的身体功能相关(B=1.14，[0.1，2.17]，R2=0.03)，在调整潜在的混杂因素后仍然显著。峰值电源频率与身体功能无关。
结论：低肌肉稳定性与低肌肉力量和较差的自我报告的身体机能弱相关。肌肉稳定性和肌肉力量似乎是肌肉功能的不同属性。没有令人信服的证据表明，肌肉稳定是研究膝骨关节炎患者身体功能的重要辅助手段。
目的：确定膝关节骨性关节炎患者膝关节伸肌稳定性与最大自主扭矩和身体功能的关系。
方法：使用来自177名随机临床试验患者的基线数据。等速膝关节伸展扭矩被处理为最大自愿扭矩[Nm]。肌肉稳定性表示为变异系数[%]和峰值功率频率[Hz]。使用西安大略省和麦克马斯特大学骨关节炎指数评估身体功能，上上下下和爬楼梯测试。使用回归分析确定关联，并针对混杂因素进行校正。
结果：较低的肌肉稳定性(即，较高的变异系数和峰值功率频率)与较低的最大主动转矩(B=-7.38，[-10.8，-3.95]，R2=0.10，B=-14.71，[-28.29，-1.13]，R2分别=0.03)。较高的变异系数与较低的自我报告的身体功能相关(B=1.14，[0.1，2.17]，R2=0.03)，在调整潜在的混杂因素后仍然显著。峰值电源频率与身体功能无关。
结论：低肌肉稳定性与低肌肉力量和较差的自我报告的身体机能弱相关。肌肉稳定性和肌肉力量似乎是肌肉功能的不同属性。没有令人信服的证据表明，肌肉稳定是研究膝骨关节炎患者身体功能的重要辅助手段。
