Department of Exercise and Sport Science, East Carolina University, Greenville, NC 27858, USA.
J Gerontol A Biol Sci Med Sci. 2011 May;66(5):541-7. doi: 10.1093/gerona/glr008. Epub 2011 Feb 23.
The net metabolic cost of walking (C(w)) as well as the level of neural activation of agonist and antagonist leg muscles are higher in healthy old compared with young adults. This study examined the association between C(w) and agonist muscle activity and antagonist coactivity in young and old adults.
Young and old adults walked at 0.98 m/s on a treadmill set at 6% decline, level, and 6% incline, while C(w) and neural activation of leg muscles were measured.
C(w) was 7.0% (incline), 19.2% (level), and 47.3% (decline) higher in old adults (overall 18.3%). Old (67.1%) versus young (40.1%) adults activated their leg muscles 67.3% more during the gait tasks and had 152.8% higher antagonist muscle coactivation (old: 67.1%, young: 19.9%). Agonist muscle activation was unrelated to C(w) on incline, but it explained up to 42% (level), 48% (decline), and 70% (three tasks combined) of variance in C(w). Antagonist coactivation accounted for up to 41% (incline), 45% (level), 59% (decline), 39% (three tasks combined) of variance in C(w).
Age-related adaptations in the recruitment pattern of leg muscles during gait significantly contribute to the high C(w) in old adults. Clinical interventions optimizing the neural control of leg muscles during gait could reduce C(w) consequently the relative effort needed for exercise and activities of daily living in old adults.
与年轻人相比，健康老年人在行走时的净代谢成本（C(w)）以及主动肌和拮抗肌的神经激活水平更高。本研究旨在探讨年轻人和老年人行走时 C(w)与主动肌活动和拮抗肌共激活之间的关系。
年轻人和老年人在跑步机上以 0.98m/s 的速度行走，坡度分别为 6%、水平和 6%，同时测量行走时的 C(w)和腿部肌肉的神经激活。
老年人在斜面上行走时的 C(w)增加了 7.0%（斜面）、19.2%（水平）和 47.3%（斜面）（总体增加 18.3%）。与年轻人（40.1%）相比，老年人（67.3%）在步态任务中激活腿部肌肉的程度更高，拮抗肌共激活程度更高，为 152.8%（老年人：67.3%，年轻人：19.9%）。在斜面上，主动肌激活与 C(w)无关，但在水平和斜面上分别解释了 C(w)的 42%（水平）、48%（斜）和 70%（三种任务总和）的变化。拮抗肌共激活在斜面上占 C(w)的 41%（斜面）、45%（水平）、59%（斜面）、39%（三种任务总和）的变化。
老年人行走时腿部肌肉募集模式的年龄相关适应性是导致老年人 C(w)高的重要原因。优化行走时腿部肌肉的神经控制的临床干预措施可能会降低 C(w)，从而降低老年人进行日常锻炼和活动所需的相对努力。
