Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
J Appl Physiol (1985). 2012 Jul;113(2):255-62. doi: 10.1152/japplphysiol.00947.2011. Epub 2012 May 17.
The purposes of this study were to determine 1) the relationships of self-reported function scores in patients with knee osteoarthritis (OA) to both maximal isometric torque and to isotonic power at a variety of loads, and 2) the degree to which muscle volume (MV) or voluntary activation (VA) are associated with torque and power measures in this population. Isometric maximal voluntary contraction (MVC) torque and isotonic power [performed at loads corresponding to 10, 20, 30, 40, and 50% MVC, and a minimal load ("Zero Load")] were measured in 40 participants with knee OA. Functional ability was measured with the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function subscale. MV was determined with magnetic resonance imaging, and VA was measured with the interpolated twitch technique. In general, power measured at lower loads (Zero Load and 10-30% MVC, r(2) = 0.21-0.28, P < 0.05) predicted a greater proportion of the variance in function than MVC torque (r(2) = 0.18, P < 0.05), with power measured at Zero Load showing the strongest association (r(2) = 0. 28, P < 0.05). MV was the strongest predictor of MVC torque and power measures in multiple regression models (r(2) = 0.42-0.72). VA explained only 6% of the variance in MVC torque and was not significantly associated with power at any load (P > 0.05). Quadriceps MVC torque and power are associated with self-reported function in knee OA, but muscle power at lower loads is more predictive of function than MVC torque. The variance in MVC torque and power between participants is due predominantly to differences in MV and has little to do with deficits in VA.
1）膝关节骨关节炎（OA）患者的自我报告功能评分与最大等长扭矩以及各种负荷下的等速功率之间的关系；2）肌肉量（MV）或自愿激活（VA）与该人群中扭矩和功率测量值的相关程度。在 40 名膝关节 OA 患者中测量了等长最大自愿收缩（MVC）扭矩和等速功率[在对应于 10、20、30、40 和 50% MVC 的负荷以及最小负荷（“零负荷”）下进行]。功能能力通过西部安大略省和麦克马斯特骨关节炎指数（WOMAC）功能量表进行测量。MV 通过磁共振成像确定，VA 通过插值抽搐技术进行测量。一般来说，较低负荷（零负荷和 10-30% MVC，r²=0.21-0.28，P<0.05）下测量的功率比 MVC 扭矩（r²=0.18，P<0.05）更能预测功能的变化，零负荷下测量的功率具有最强的相关性（r²=0.28，P<0.05）。MV 是多回归模型中 MVC 扭矩和功率测量的最强预测因子（r²=0.42-0.72）。VA 仅解释了 MVC 扭矩方差的 6%，并且与任何负荷下的功率均无显著相关性（P>0.05）。股四头肌 MVC 扭矩和功率与膝关节 OA 的自我报告功能相关，但较低负荷下的肌肉功率比 MVC 扭矩更能预测功能。参与者之间的 MVC 扭矩和功率差异主要归因于 MV 的差异，而与 VA 缺陷关系不大。
