Marsh Anthony P, Miller Michael E, Saikin Aaron M, Rejeski W Jack, Hu Nan, Lauretani Fulvio, Bandinelli Stefania, Guralnik Jack M, Ferrucci Luigi
Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC 27109-7868, USA.
J Gerontol A Biol Sci Med Sci. 2006 Nov;61(11):1186-93. doi: 10.1093/gerona/61.11.1186.
It has been suggested that lower extremity muscle power is more important for physical function in older adults compared to strength, and that there is a nonlinear relationship between power or strength and physical function that might be indicative of a threshold above which the association between muscle function and physical function is no longer evident. This study examined the association between lower extremity strength or power with the time to complete a 400-meter walk, and attempted to identify thresholds within the relationship.
A cross-sectional analysis of a sample of 384 females and 336 males aged > or = 65 years from the InCHIANTI study ("Invecchiare in Chianti," i.e., Aging in the Chianti Area) was conducted. Measures included 400-meter walk time, lower extremity strength and power, comorbidities, and sociodemographic variables (age, gender, height, education, cognitive function, depression).
Linear regression models showed that both lower extremity strength and power were significant predictors of 400-meter walk time, although power explained marginally more of the variance in 400-meter walk time. Quadratic models of lower extremity strength and power fit the data slightly better than the linear models. Regardless of gender, comorbidities, or normalization scheme for strength and power, the curvilinear form of the relationship between strength or power and 400-meter walk time remained the same.
Lower extremity muscle strength and power are both important predictors of the 400-meter walk time. Although curvilinear relationships existed between muscle strength and power and the 400-meter walk time, the data do not indicate a clear threshold for either strength or power above which the performance in the 400-meter walk test plateaus.
有人提出，与力量相比，下肢肌肉力量对老年人的身体功能更为重要，而且力量或肌肉力量与身体功能之间存在非线性关系，这可能表明存在一个阈值，超过该阈值，肌肉功能与身体功能之间的关联不再明显。本研究探讨了下肢力量或肌肉力量与完成400米步行时间之间的关联，并试图确定该关系中的阈值。
对来自InCHIANTI研究（“Invecchiare in Chianti”，即基安蒂地区老龄化研究）的384名年龄≥65岁的女性和336名男性样本进行了横断面分析。测量指标包括400米步行时间、下肢力量和肌肉力量、合并症以及社会人口统计学变量（年龄、性别、身高、教育程度、认知功能、抑郁）。
线性回归模型显示，下肢力量和肌肉力量都是400米步行时间的显著预测因素，尽管肌肉力量对400米步行时间方差的解释略多一些。下肢力量和肌肉力量的二次模型比线性模型对数据的拟合稍好。无论性别、合并症或力量和肌肉力量的标准化方案如何，力量或肌肉力量与400米步行时间之间关系的曲线形式保持不变。
下肢肌肉力量和肌肉力量都是400米步行时间的重要预测因素。尽管肌肉力量和肌肉力量与400米步行时间之间存在曲线关系，但数据并未表明力量或肌肉力量存在明确的阈值，超过该阈值后400米步行测试中的表现趋于平稳。
