Suda Yuki, Higuchi Takahiro
Department of Health Promotion Science, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, 192-0397, Japan.
Japan Society for the Promotion of Science, Tokyo, Japan.
J Neuroeng Rehabil. 2024 Dec 21;21(1):224. doi: 10.1186/s12984-024-01532-5.
An age-related decline in motor flexibility, which is the ability to synergistically control the degrees of freedom of the body to ensure stable performance of a task, is a factor that contributes to falls. We investigated whether providing environmental constraints to increase the movement repertoire (i.e., the motor solution that works to achieve one's goal), in combination with aiming at precise control of the performance, would be effective for improving motor flexibility, and whether the effect on the leading limb would extend to the trailing limb.
Fifteen older adults (75.1 ± 6.2 years and 14 younger adults (34.6 ± 5.0 years) performed under three walking conditions: walking normally and crossing the obstacle (normal), walking and crossing the obstacle with constraints of foot placement after stepping over it (constrained), and walking and crossing the obstacle with constraints as in the constrained condition, in addition to aiming for maintaining a constant clearance height at the moment of obstacle crossing (precision). An uncontrolled manifold analysis was used to quantify motor flexibility as the synergy index. The foot height at the moment of obstacle crossing was used as the performance variable and seven segmental angles were used as the elemental variables. A higher synergy index indicates greater motor flexibility.
For the leading limb, the synergy index was significantly higher under the precision condition than those under the other conditions. This suggests that not only providing environmental constraints but also keeping constant the performance variable is critical to improving motor flexibility. Moreover, the effects of an increase in the synergy index in the leading limb extended to the trailing limb.
Providing environmental constraints to increase the movement repertoire while also aiming for precision in the performance variable was an effective method of improving motor flexibility during obstacle crossing for older adults.
与年龄相关的运动灵活性下降是导致跌倒的一个因素，运动灵活性是指协同控制身体自由度以确保任务稳定执行的能力。我们研究了提供环境约束以增加运动方式（即实现目标的运动解决方案），并结合精确控制运动表现，是否能有效提高运动灵活性，以及对领先肢体的影响是否会扩展到跟随肢体。
15名老年人（75.1±6.2岁）和14名年轻人（34.6±5.0岁）在三种步行条件下进行实验：正常行走并跨越障碍物（正常）；在跨过障碍物后，在足部放置受限的情况下行走并跨越障碍物（受限）；以及在受限条件下行走并跨越障碍物，此外还要在跨越障碍物时保持恒定的间隙高度（精确）。使用非受控流形分析将运动灵活性量化为协同指数。将跨越障碍物时的足部高度用作运动表现变量，将七个节段角度用作基本变量。协同指数越高表明运动灵活性越高。
对于领先肢体，精确条件下的协同指数显著高于其他条件下的协同指数。这表明不仅提供环境约束，而且保持运动表现变量恒定对于提高运动灵活性至关重要。此外，领先肢体协同指数增加的影响扩展到了跟随肢体。
提供环境约束以增加运动方式，同时在运动表现变量上追求精确性，是提高老年人跨越障碍物时运动灵活性的有效方法。
