The present study investigated the effects of aging on the distribution of common descending neural drives to main postural muscles acting on the ankle, knee, hip, and lower trunk. The presence, distribution, and strength of these drives were assessed using intermuscular coherence estimations at a low-frequency band (0–55 Hz). Ten healthy older adults (68.7 ± 3.5 years) with no recent history of falls and ten healthy younger adults (26.8 ± 2.7 years) performed bipedal stances with eyes either opened or closed. Electromyographic (EMG) signals of six postural muscles were recorded. Estimations of intermuscular coherence were obtained from fifteen muscle pairs and four muscle groups. In general, single-pair and pooled coherence analyzes revealed significant levels of signal synchronization within 1–10 Hz. Significant common drives to anterior, posterior, and antagonist muscle groups were observed for both cohorts of participants. However, older participants showed significantly stronger EMG–EMG synchronization in the frequency domain compared to younger participants. It seems that age-related sarcopenia, visual-vestibular-proprioceptive decline, cortical activation increase, presynaptic inhibition modulation decrease, and co-contraction increase had a major impact on strengthening the common drives to the aforementioned muscle groups. Differently from young adults, the absence of visual inputs did not reduce the magnitude of signal synchronization in older adults. These results suggest that the aging central nervous system seems to organize similar arrangements of common drives to postural antagonist muscles at different joints, and to postural muscles pushing the body either forward or backward when visual information is not available.

本研究调查了衰老对作用于脚踝，膝盖，臀部和下部躯干的主要姿势肌肉的常见降序神经驱动分布的影响。这些驱动器的存在，分布和强度在低频频段（0-55 Hz）使用肌间连贯性估计进行评估。10名没有近期摔倒史的健康老年人（68.7±3.5岁）和10名健康年轻成年人（26.8±2.7岁）双足站立，双眼睁开或闭上。记录了六个姿势肌肉的肌电图（EMG）信号。肌肉间连贯性的估计是从15个肌肉对和4个肌肉组中获得的。通常，单对和集合相干分析表明，在1-10 Hz范围内信号同步水平很高。向前的重要共同驱动力 两个参与者均观察到后肌群和拮抗肌群。然而，与年轻参与者相比，年长参与者在频域上表现出明显更强的EMG-EMG同步。似乎与年龄有关的肌肉减少症，视觉上的前庭本体感受力下降，皮质的激活增加，突触前的抑制调节减少以及共收缩的增加对加强对上述肌肉群的共同驱动力有重大影响。与年轻人不同，缺少视觉输入并不会降低老年人的信号同步幅度。这些结果表明，衰老的中枢神经系统似乎在不同关节处组织了对姿势拮抗肌的共同驱动的相似排列，