Hortobágyi T, Zheng D, Weidner M, Lambert N J, Westbrook S, Houmard J A
Biomechanics Laboratory, School of Health and Human Performance, East Carolina University, USA.
J Gerontol A Biol Sci Med Sci. 1995 Nov;50(6):B399-406. doi: 10.1093/gerona/50a.6.b399.
It is well established that aging seriously reduces isometric and concentric muscle strength due to atrophy, deterioration of mechanical properties, and motor unit loss. However, there is limited information on the impact of aging on eccentric strength despite the fact that such forces play an equally important role during daily activities. The purpose of this study was to examine the influence of aging on three expressions of muscle strength (isometric, concentric, and eccentric) in relation to muscle fiber characteristics, with special emphasis on eccentric force. Sedentary but healthy men (age range 18-80 years, n = 60) and women (20-74 years, n = 30) were tested for maximal effort isometric, concentric, and eccentric (1.05, 2.09, 3.14 rads.s-1) quadriceps strength, body composition, and muscle fiber characteristics of the vastus lateralis (men only). There was a significant (p < .05) approximately 30 N per decade decline in isometric and concentric forces, but only 9 N per decade reduction in eccentric strength. There was a significant reduction in Type II muscle fiber area with aging (p < .05). Isometric, eccentric, and concentric force correlated r = .33, r = .32 (p < .05), and r = .12 (p > .05) with Type II muscle fiber area, respectively. The correlation between age and fat-free mass/force ratio ranged from r = .39 to .43 in men and r = .27 to .50 in women. The data suggest a relative preservation of eccentric strength with aging in men and women that seems to be independent of muscle mass or muscle fiber type or size.
众所周知，由于肌肉萎缩、力学性能退化和运动单位丧失，衰老会严重降低等长和向心肌肉力量。然而，尽管离心力在日常活动中同样起着重要作用，但关于衰老对离心力量影响的信息却很有限。本研究的目的是研究衰老对与肌肉纤维特征相关的三种肌肉力量表现形式（等长、向心和离心）的影响，特别强调离心力。对久坐但健康的男性（年龄范围18 - 80岁，n = 60）和女性（20 - 74岁，n = 30）进行了最大努力的等长、向心和离心（1.05、2.09、3.14弧度·秒⁻¹）股四头肌力量、身体成分以及外侧股四头肌（仅男性）的肌肉纤维特征测试。等长和向心力量每十年显著下降约30牛（p < 0.05），但离心力量每十年仅下降9牛。随着年龄增长，II型肌纤维面积显著减少（p < 0.05）。等长、离心和向心力量与II型肌纤维面积的相关性分别为r = 0.33、r = 0.32（p < 0.05）和r = 0.12（p > 0.05）。男性年龄与去脂体重/力量比值的相关性在r = 0.39至0.43之间，女性在r = 0.27至0.50之间。数据表明，男性和女性衰老过程中离心力量相对保持，这似乎与肌肉质量、肌肉纤维类型或大小无关。
