School of Physical Therapy, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil.
Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Braz J Phys Ther. 2014 Mar-Apr;18(2):183-90. doi: 10.1590/s1413-35552012005000145. Epub 2014 Mar 19.
Aging is a multifactorial process that leads to changes in the quantity and quality of skeletal muscle and contributes to decreased levels of muscle strength.
This study sought to investigate whether the isometric muscle strength, fat-free mass (FFM) and power of the electromyographic (EMG) signal of the upper and lower limbs of women are similarly affected by aging.
The sample consisted of 63 women, who were subdivided into three groups (young (YO) n=33, 24.7 ± 3.5 years; middle age (MA) n=15, 58.6 ± 4.2 years; and older adults (OA). n=15, 72.0 ± 4.2 years). Isometric strength was recorded simultaneously with the capture of the electrical activity of the flexor muscles of the fingers and the vastus lateralis during handgrip and knee extension tests, respectively. FFM was assessed using dual-energy X-ray absorptiometry.
The handgrip strength measurements were similar among groups (p=0.523), whereas the FFM of the upper limbs was lower in group OA compared to group YO (p=0.108). The RMSn values of the hand flexors were similar among groups (p=0.754). However, the strength of the knee extensors, the FFM of the lower limbs and the RMSn values of the vastus lateralis were lower in groups MA (p=0.014, p=0.006 and p=0.013, respectively) and OA (p=0.000, p=0.000 and p<0.000, respectively) compared to group YO.
The results of this study demonstrate that changes in isometric muscle strength in MLG and electromyographic activity of the lower limbs are more pronounced with the aging process of the upper limb.
衰老 是一个多因素的过程，导致骨骼肌数量和质量的变化，并导致肌肉力量水平下降。
本研究旨在探讨女性上下肢等速肌肉力量、去脂体重（FFM）和肌电图（EMG）信号功率是否同样受到衰老的影响。
该样本由 63 名女性组成，分为三组（年轻组（YO）n=33，24.7±3.5 岁；中年组（MA）n=15，58.6±4.2 岁；和老年组（OA）n=15，72.0±4.2 岁）。在握力和膝关节伸展测试中，分别同时记录手指屈肌的等长力量和股外侧肌的电活动。使用双能 X 射线吸收法评估 FFM。
各组间握力测量值相似（p=0.523），但 OA 组上肢 FFM 低于 YO 组（p=0.108）。手部屈肌的 RMSn 值在各组间相似（p=0.754）。然而，股四头肌的力量、下肢的 FFM 和股外侧肌的 RMSn 值在 MA 组（p=0.014、p=0.006 和 p=0.013，分别）和 OA 组（p=0.000、p=0.000 和 p<0.000，分别）均低于 YO 组。
本研究结果表明，上肢衰老过程中，下肢 MLG 等速肌肉力量和肌电图活动的变化更为明显。
