Kwon I S, Oldaker S, Schrager M, Talbot L A, Fozard J L, Metter E J
National Institute on Aging, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
J Gerontol A Biol Sci Med Sci. 2001 Sep;56(9):B398-404. doi: 10.1093/gerona/56.9.b398.
We examined the effects of age and gender on the relationship between knee strength and walking time during a walk-turn-walk test in 176 male and 168 female generally healthy participants of the Baltimore Longitudinal Study of Aging who were aged 21-89 years. Subjects were timed as they walked 50 ft (15.24 m), turned around, and walked back to the starting point, both at a comfortable pace and as fast as possible. Isokinetic concentric knee extensor strength was measured at 30 degrees /s by using a Kin-Com dynamometer. Both comfortable and fast gait times increased with increasing age for both women and men, starting in middle age. An interaction was found between gender and age showing that older women are slower than older men at both paces. Gait time decreased linearly with increasing knee extensor strength, plateauing at higher strength levels (>130 N m for comfortable gait, and 190 N m for fast gait). Most women occupied the linear part of the curve below the plateau. Adjustment for body size, age, physical activity, and particularly number of steps to complete the task removed the relationship between strength and gait time for the comfortable gait. Women took longer to complete the walk-turn-walk test than men at older ages, were on the linear part of the strength-gait time relationship, and used more steps to complete the task, all of which may contribute to their greater likelihood of frailty in later years.
我们在巴尔的摩纵向衰老研究中，对176名年龄在21至89岁之间的男性和168名年龄相仿的女性一般健康参与者进行了走-转-走测试，研究年龄和性别对膝关节力量与步行时间之间关系的影响。受试者以舒适的步伐和尽可能快的速度行走50英尺（15.24米），转身，然后走回起点，记录所用时间。使用等速肌力测试仪在30度/秒的速度下测量膝关节伸肌的等速向心收缩力量。对于男性和女性，从中年开始，随着年龄的增长，舒适步态和快速步态的时间均增加。发现性别和年龄之间存在交互作用，表明在两种步伐下，老年女性都比老年男性慢。随着膝关节伸肌力量的增加，步态时间呈线性下降，在较高力量水平（舒适步态>130牛米，快速步态>190牛米）时趋于平稳。大多数女性处于曲线平稳段以下的线性部分。对身体大小、年龄、身体活动，尤其是完成任务的步数进行调整后，舒适步态下力量与步态时间之间的关系消失。在老年时，女性完成走-转-走测试的时间比男性长，处于力量-步态时间关系的线性部分，且完成任务使用的步数更多，所有这些因素可能导致她们在晚年更易出现身体虚弱。
