Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA.
Department of Neurology, Norman Fixel Institute of Neurological Disorders, University of Florida, Gainesville, FL, 32611, USA.
Sci Rep. 2021 Apr 7;11(1):7562. doi: 10.1038/s41598-021-86959-9.
Here, we aimed to understand if older adults (OA) use a unique motor plan that is detrimental to endpoint control. We performed two experiments that used ankle ballistic contractions that reversed at the target. In Experiment 1, eight young adults (YA; 27.1 ± 4.2) and eight OA (73.3 ± 4.5) aimed to perform an ankle dorsiflexion-plantarflexion movement that reversed at 9° in 180 ms (target). We found that the coordination pattern (motor plan) differed for the two groups. OA used significantly greater soleus (SOL) activity to reverse the ankle movement than YA and exhibited greater tibialis anterior (TA) muscle activity variability (p < 0.05). OA exhibited worse endpoint control than YA, which associated with the exacerbated TA variability (R > 0.2; p < 0.01). Experiment 2 aimed to confirm that the OA motor plan was detrimental to endpoint control. Fifteen YA (20.5 ± 1.4) performed an ankle dorsiflexion-plantarflexion contraction that reversed at 30% MVC in 160 ms by using either a pattern that mimicked OA (High SOL) or YA (Low SOL). With the High SOL coordination pattern, YA exhibited impaired endpoint control and greater TA activation variability. These findings provide strong evidence that OA select a unique motor plan that is detrimental to endpoint control.
在这里，我们旨在了解老年人（OA）是否使用独特的运动计划，而这种计划不利于终点控制。我们进行了两项实验，均使用踝关节弹击收缩，在目标处反转。在实验 1 中，8 名年轻成年人（YA；27.1±4.2）和 8 名 OA（73.3±4.5）旨在完成一个在 180 毫秒内反转 9°的踝关节背屈-跖屈运动（目标）。我们发现，两组的协调模式（运动计划）不同。OA 为反转踝关节运动而使用的比目鱼肌（SOL）活动显著大于 YA，并且表现出更大的胫骨前肌（TA）肌肉活动可变性（p<0.05）。OA 的终点控制比 YA 差，这与 TA 可变性加剧有关（R>0.2；p<0.01）。实验 2旨在证实 OA 的运动计划不利于终点控制。15 名 YA（20.5±1.4）在 160 毫秒内以 30%最大收缩力（MVC）进行踝关节背屈-跖屈收缩，使用模仿 OA（高 SOL）或 YA（低 SOL）的模式。使用高 SOL 协调模式时，YA 表现出终点控制受损和更大的 TA 激活可变性。这些发现提供了有力的证据，表明 OA 选择了一种独特的运动计划，不利于终点控制。
