Pua Yong-Hao, Wrigley Tim V, Collins Marnie, Cowan Sallie M, Bennell Kim L
The University of Melbourne, Melbourne, Victoria, Australia.
Arthritis Rheum. 2009 Apr 15;61(4):442-50. doi: 10.1002/art.24344.
To examine whether the associations of physical performance with isometric hip and knee extensors strength and passive hip flexion and internal rotation range of motion (ROM) are nonlinear in community-dwelling adults with hip osteoarthritis (OA).
Participants were 100 adults (mean age 62 years) with radiographically confirmed hip OA. Physical performance measures included gait speed test and timed stair tests. Piecewise regression models of muscle strength and hip ROM on physical performance measures were used to identify possible breakpoints. Receiver operating characteristic (ROC) curve analysis was used to identify participants with functionally inadequate (< or =1.0 meters/second) gait speed and optimal cut points were identified.
Muscle strength and hip ROM were nonlinearly associated with stair measures but not with gait speed measures. The optimal breakpoints and ROC-derived cut points were 1.8-2.5Nm/kg for knee extensors, 1.5-2.1Nm/kg for hip extensors, 25-26 degrees for hip internal rotation ROM, and 109-115 degrees for hip flexion ROM. Muscle strength breakpoints increased monotonically with increasing movement demand.
In individuals with hip OA, the associations between physical performance and measures of muscle strength and hip ROM are less straightforward than previously assumed. These breakpoints and ROC-derived cut points may be useful in identifying individuals for whom interventions that improve muscle strength or hip ROM would be most beneficial.
探讨在患有髋骨关节炎（OA）的社区居住成年人中，身体机能与等长髋关节和膝关节伸肌力量以及髋关节被动屈曲和内旋活动范围（ROM）之间的关联是否呈非线性。
研究对象为100名经X线检查确诊为髋OA的成年人（平均年龄62岁）。身体机能测量包括步态速度测试和定时上楼梯测试。采用肌肉力量和髋关节ROM对身体机能测量的分段回归模型来确定可能的断点。使用受试者工作特征（ROC）曲线分析来识别步态速度功能不足（≤1.0米/秒）的参与者，并确定最佳切点。
肌肉力量和髋关节ROM与上楼梯测量呈非线性相关，但与步态速度测量无关。膝关节伸肌的最佳断点和ROC得出的切点为1.8 - 2.5牛米/千克，髋关节伸肌为1.5 - 2.1牛米/千克，髋关节内旋ROM为25 - 26度，髋关节屈曲ROM为109 - 115度。肌肉力量断点随运动需求增加而单调增加。
在患有髋OA的个体中，身体机能与肌肉力量和髋关节ROM测量之间的关联比之前假设的更为复杂。这些断点和ROC得出的切点可能有助于识别那些改善肌肉力量或髋关节ROM的干预措施最有益的个体。
