Chuang Yu-Fen, Chen Chih-Chung, Hsu Miao-Ju, Huang Nan-Jing, Huang Ying-Zu, Chan Hsiao-Lung, Chang Ya-Ju
School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.
Department of Physical Therapy, College of Health Science, Kaohsiung Medical University; Department of Physical Medicine and Rehabilitation, and Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
J Electromyogr Kinesiol. 2019 Feb;44:132-138. doi: 10.1016/j.jelekin.2018.12.007. Epub 2018 Dec 24.
The purpose was to investigate the age effects on central versus peripheral sources of strength, fatigue, and central neural excitabilities.
42 healthy subjects were recruited as young group (23.73 ± 2.15 years; n = 26) and middle-aged group (57.25 ± 4.57 years; n = 16). Maximum voluntary contraction force (MVC), voluntary activation level (VA), and twitch force of quadriceps were evaluated to represent general, central, and peripheral strengths. Central and peripheral fatigue indexes were evaluated using femoral nerve electrical stimulation. Cortical excitabilities were evaluated using transcranial magnetic stimulation (TMS).
The middle-aged group had lower MVC and twitch force of quadriceps, but not VA, than young group. No between group differences were found in fatigue indexes. The cortical excitability in middle-aged group was different from young group in paired TMS with inter-stimulus interval of 7 ms.
The age-related strength loss at early stage was primarily caused by peripheral muscular strength. The deviation of central neural excitability can be detected but the activation level was not impaired in middle-age adults.
目的是研究年龄对力量、疲劳的中枢与外周来源以及中枢神经兴奋性的影响。
招募42名健康受试者，分为年轻组（23.73 ± 2.15岁；n = 26）和中年组（57.25 ± 4.57岁；n = 16）。评估股四头肌的最大自主收缩力（MVC）、自主激活水平（VA）和抽搐力，以代表总体、中枢和外周力量。使用股神经电刺激评估中枢和外周疲劳指数。使用经颅磁刺激（TMS）评估皮质兴奋性。
中年组股四头肌的MVC和抽搐力低于年轻组，但VA无差异。两组之间的疲劳指数无差异。在刺激间隔为7毫秒的配对TMS中，中年组的皮质兴奋性与年轻组不同。
早期与年龄相关的力量损失主要由外周肌肉力量引起。中年成年人可检测到中枢神经兴奋性的偏差，但激活水平未受损。
