Force control is impaired in the ankle plantarflexors of elderly adults.
Force control is impaired in the ankle plantarflexors of elderly adults.
复制标题
老年人的踝跖屈肌的力控制能力受损。
DOI：
10.1007/s00421-007-0538-0
复制
发表时间：
2007
影响因子：
3
通讯作者：
Tracy,BrianL
中科院分区：
文献类型：
--
作者：
Tracy,BrianL
本研究确定了年轻人和老年人踝关节背屈肌（DF）和跖屈肌（PF）的力波动幅度。对11名青年（23±3岁，5名女性，6名男性）和10名老年人（73±6岁，5名女性，5名男性）进行了最大自主收缩力（MVC）和等距DF和PF稳定性（2.5-80% MVC）的评估。通过稳定性试验测量了力的变异系数（CV）和功率谱。老年人PF的MVC力较低（降低38%，P= 0.002），但DF不低（降低20%，P= 0.14）。对于PF，老年人的CV大于年轻人，分别为2.5% （2.64 vs. 1.71%）和5% MVC (1.78 vs. 1.24%)，在10%、50%和80% MVC时相似，在30% MVC目标力时，年轻人的CV大于老年人。对于DF，在所有目标力下，青年和老年人的力CV相似（P < 0.05）。在所有目标力中，PF肌肉的力CV比DF肌肉低49% （P< 0.0001）。与更高的目标力相比，2.5（58%）、5（58%）和10% MVC（44%）目标力的差异明显更大。两种肌肉的力波动的功率谱始终以低于2赫兹的频率为主。对于老年人来说，踝关节跖屈肌而不是背屈肌的神经肌肉因素在低力收缩时影响肌力和力波动。
This study determined the amplitude of force fluctuations for the ankle dorsiflexor (DF) and plantarflexor (PF) muscles of young and elderly adults. Maximal voluntary contraction (MVC) force and isometric DF and PF steadiness (2.5–80% MVC) was assessed in 11 young (23 ± 3 years, 5 women, 6 men) and 10 elderly (73 ± 6 years, 5 women, 5 men) adults. The coefficient of variation (CV) and power spectrum of the force was measured from the steadiness trials. MVC force was lower for elderly adults for PF (38% lower,P= 0.002) but not DF (20% lower,P= 0.14). For PF, the CV of force was greater for elderly than young adults at 2.5% (2.64 vs. 1.71%) and 5% MVC (1.78 vs. 1.24%), similar at 10, 50, and 80% MVC, and greater for young than elderly at the 30% MVC target force. For DF, the CV of force was similar for young and elderly at all target forces (P> 0.05). The CV of force was 49% lower for the PF compared with DF muscles across all target forces (P< 0.0001). This difference was significantly greater at the 2.5 (58%), 5 (58%), and 10% MVC (44%) target forces compared with higher target forces. The power spectra of the force fluctuations for both muscles were consistently dominated by frequencies below 2 Hz. For elderly adults, the neuromuscular factors that underlie both muscle strength and force fluctuations during low-force contractions are impaired in the ankle plantarflexors but not the dorsiflexors.