Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom.
Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom.
J Biomech. 2019 Feb 14;84:243-246. doi: 10.1016/j.jbiomech.2018.12.011. Epub 2018 Dec 12.
Perturbation training is an emerging approach to reduce fall risk in the elderly. This study examined potential differences in retention of improvements in reactive gait stability over 14 weeks resulting from unexpected trip-like gait perturbations. Twenty-four healthy middle-aged adults (41-62 years) were assigned randomly to either a single perturbation group (SINGLE, n = 9) or a group subjected to eight trip-like gait perturbations (MULTIPLE, n = 15). While participants walked on a treadmill a custom-built brake-and-release system was used to unexpectedly apply resistance during swing phase to the lower right limb via an ankle strap. The anteroposterior margin of stability (MoS) was calculated as the difference between the anterior boundary of the base of support and the extrapolated centre of mass at foot touchdown for the perturbed step and the first recovery step during the first and second (MULTIPLE group only) perturbation trials for the initial walking session and retention-test walking 14 weeks later. Group MULTIPLE retained the improvements in reactive gait stability to the perturbations (increased MoS at touchdown for perturbed and first recovery steps; p < 0.01). However, in group SINGLE no differences in MoS were detected after 14 weeks compared to the initial walking session. These findings provide evidence for the requirement of a threshold trip-perturbation dose if adaptive changes in the human neuromotor system over several months, aimed at the improvement in fall-resisting skills, are to occur.
扰动训练是一种降低老年人跌倒风险的新兴方法。本研究考察了在 14 周的时间内，由于意外的类似绊倒的步态扰动，反应性步态稳定性的改善在保持方面的潜在差异。24 名健康的中年成年人（41-62 岁）被随机分配到单次扰动组（SINGLE，n=9）或接受 8 次类似绊倒的步态扰动的组（MULTIPLE，n=15）。当参与者在跑步机上行走时，一个定制的刹车和释放系统被用来通过脚踝带在摆动阶段意外地向右侧下肢施加阻力。前后向稳定度（MoS）是通过在初始行走阶段和 14 周后的保留测试行走期间，在第一次和第二次（仅 MULTIPLE 组）扰动试验中，计算受扰步和第一恢复步的支撑基础的前边界与脚触地点的质量中心的外推之间的差异来计算的。MULTIPLE 组保留了对扰动的反应性步态稳定性的改善（受扰和第一恢复步的触地点 MoS 增加；p<0.01）。然而，在 SINGLE 组中，与初始行走阶段相比，14 周后 MoS 没有差异。这些发现为人类神经运动系统在几个月内的适应性变化提供了证据，如果要提高抗跌倒技能，就需要一个阈值的绊倒扰动剂量。
