AIM To assess the change in the contribution of proprioceptive signal from leg muscles in postural control with ageing. METHODS Fifteen young (~23 yr) and fifteen older adults (~68 yr) participated in Experiment 1, which consisted of recording the mean position of the centre of pressure (CoP), CoP path length, CoP velocity, and the amplitude of the Hoffmann (H) reflex and maximal M wave (MMAX) in the soleus muscle during upright standing, before and after 1 h of bilateral Achilles tendon vibration applied in seated posture. Eight young (~24 yr) and eight older adults (~67 yr) participated in Experiment 2 consisting of recording H-reflex and MMAX in seated posture before and after the 1-h vibration procedure used in Experiment 1. RESULTS Immediately after the 1-h vibration, the mean CoP position shifted forward in both groups (p < 0.05), with a greater magnitude of change (% pre-vibration) in young [mean(SD); 74(41)%] than older adults [44(40)%; p < 0.05]. The CoP path length and velocity only increased in young adults after vibration (p < 0.05). The H-reflex amplitude decreased only in young adults after vibration [before: 35(12); after: 16(13)% Mmax, p < 0.05] during upright standing (Experiment 1), whereas it decreased similarly (p > 0.05) in young [before: 47(12)% Mmax; after: 28(17)% Mmax] and older adults [before: 34(13)% Mmax; after: 21(14)% Mmax] in seated posture (Experiment 2). CONCLUSION Prolonged Achilles tendon vibrations lead to lesser postural perturbation in older than in young adults, supporting the assumption of a decreased reliance on leg muscle proprioception in postural control with ageing.

中文翻译：

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老年人跟腱振动时间延长对姿势控制的影响减少。

目的评估随着年龄的增长，姿势控制中腿部肌肉对本体感受信号的贡献的变化。方法15名年轻人（约23岁）和15名老年人（约68岁）参加了实验1，该实验包括记录压力中心（CoP）的平均位置，CoP路径长度，CoP速度和振幅直立站立期间，坐姿施加双侧跟腱腱振动1小时之前和之后，比目鱼肌的霍夫曼（H）反射和最大M波（MMAX）。八名年轻人（约24岁）和八名成年人（约67岁）参加了实验2，包括在实验1进行1h振动程序前后，以坐姿记录H反射和MMAX。结果1 -h振动，两组的平均CoP位置向前移动（p <0.05），年轻[平均（SD）；74（41）％]比老年人[44（40）％；p ＜0.05]。CoP路径长度和速度仅在振动后的年轻人中增加（p <0.05）。H反射幅度仅在振动后的年轻人中降低[之前：35（12）；之后：直立站立时（实验1）的Mmax为16（13）％，p <0.05]，而年轻时[之前：47（12）％的Mmax，其相似地下降（p> 0.05）；之后：28（17）％Mmax]和老年人[之前：34（13）％Mmax；之后：就座姿势（实验2）达到21（14）％Mmax]。结论与老年人相比，跟腱长期振动导致的体位干扰较小，这支持以下假设：随着年龄的增长，在姿势控制中对腿部肌肉本体感受的依赖性降低。