Rantanen T, Guralnik J M, Izmirlian G, Williamson J D, Simonsick E M, Ferrucci L, Fried L P
Epidemiology, Demography and Biometry Program, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20892, USA.
Am J Phys Med Rehabil. 1998 Jul-Aug;77(4):299-305. doi: 10.1097/00002060-199807000-00008.
Our aim was to study the association of lower limb strength with maximum walking speed in disabled older women and to try to detect the reserve capacity threshold for maximum walking speed and the minimum strength required for walking at a speed of 1.22 m x s(-1), which is required in crossing signaled intersections. The data are from the baseline of Women's Health and Aging Study, a population-based study on causes and course of disability. Altogether, 1,002 disabled women participated in the tests, which took place at their homes. Maximum isometric hip flexion and knee extension forces were measured on both sides using a handheld dynamometer. For analytic purposes, knee extension torque/body mass ratio (KET/BM) was calculated. Maximum walking speed was measured with a stopwatch during a 4-m walk. KET/BM had a significant effect on walking speed after controlling for number of chronic conditions, balance, use of walking aid, joint pain, age, and body height and mass. A total of 42.3% of the variation in maximum walking speed was explained by these variables. The cumulative percentage distribution of KET/BM of those able to attain a maximum walking speed of 1.22 m x s(-1) (n = 148) was flat to the level of 1.1 N x m x kg(-1), after which it turned upward, indicating that the probability of attaining 1.22 m x s(-1) started to increase after that level. By using segmented linear regression analysis, 2.3 N x m x kg(-1) was found to be the cutoff point beyond which an increase in KET/BM did not correspond to an increase in maximum walking speed. Muscle strength was positively but not linearly associated with maximum walking speed. Strength testing may help to identify people close to functional thresholds and, thus, at risk of impaired walking, who would benefit most from strengthening exercises.
我们的目的是研究残疾老年女性下肢力量与最大步行速度之间的关联，并试图检测最大步行速度的储备能力阈值以及以1.22米/秒（-1）的速度行走所需的最小力量，这是通过有信号的十字路口时所需要的速度。数据来自女性健康与衰老研究的基线，这是一项基于人群的关于残疾原因和病程的研究。共有1002名残疾女性在家中参加了测试。使用手持测力计测量双侧最大等长髋部屈曲和膝部伸展力量。为了分析目的，计算了膝部伸展扭矩/体重比（KET/BM）。在4米步行过程中用秒表测量最大步行速度。在控制了慢性病数量、平衡能力、助行器使用情况、关节疼痛、年龄以及身高和体重后，KET/BM对步行速度有显著影响。这些变量解释了最大步行速度变化的42.3%。能够达到最大步行速度1.22米/秒（-1）的人群（n = 148）的KET/BM累积百分比分布在1.1牛·米/千克（-1）水平之前是平缓的，之后向上转折，表明在该水平之后达到1.22米/秒（-1）的概率开始增加。通过分段线性回归分析，发现2.3牛·米/千克（-1）是临界点，超过该点KET/BM的增加与最大步行速度的增加不再对应。肌肉力量与最大步行速度呈正相关但不是线性相关。力量测试可能有助于识别接近功能阈值、因此有行走障碍风险的人群，这些人将从强化锻炼中受益最大。
