不同类型和负荷双任务对健康人动态姿势控制的影响

Effects of Dual Tasks with Different Types and Loads on Dynamic Postural Control in Healthy Adults

目的通过对比不同负荷认知双任务行走和运动双任务行走时下肢表面肌电(surface electromyography,sEMG)信号及动态稳定性的差异,探究不同类型和负荷双任务对健康人动态姿势控制的影响。方法利用无线sEMG测试仪和三维运动捕捉系统同时采集28名受试者不同负荷认知双任务行走和运动双任务行走时平均肌电(average electromyography,AEMG)和动态稳定性指标。采用双因素重复测量方差分析任务类型(认知任务和运动任务)和任务负荷(简单任务和困难任务)对人体下肢sEMG和动态稳定性的影响以及两者之间的交互作用。结果简单负荷行走时,左右股二头肌和右胫前肌AEMG均小于困难负荷行走(P<0.05),左胫前肌简单运动双任务行走时AEMG小于困难运动双任务行走(P<0.05)。右腓肠肌困难认知双任务行走时AEMG小于困难运动双任务行走(P<0.05),简单认知双任务行走时AEMG大于困难认知双任务行走(P<0.05),简单运动双任务行走时AEMG小于困难运动双任务行走(P<0.05);简单认知双任务行走动态稳定裕度(margins of stability,MoS)大于简单运动双任务行走(P<0.05),困难认知双任务行走MoS小于困难运动双任务行走(P<0.05),简单运动双任务行走MoS小于困难运动双任务行走(P<0.05)。结论不同类型和负荷双任务对动态姿势控制的影响存在交互效应。困难运动双任务行走时踝关节周围肌肉的神经肌肉控制和动态稳定性强于困难认知双任务行走,困难运动双任务行走时踝关节周围肌肉的神经肌肉控制和动态稳定性强于简单运动双任务行走。

Objective By comparing the differences of surface electromyography(sEMG)signals and dynamic stability of lower limbs during cognitive dual-task walking and motor dual-task walking under different loads,the effects of dual tasks with different types and loads on dynamic postural control in healthy adults were investigated.Methods The average electromyography(AEMG)and dynamic stability indexes of 28 subjects during cognitive dual-task walking and motor dual-task walking under different loads were collected by wireless sEMG tester and three-dimensional(3D)motion capture system.The effects of task type(cognitive task and motor task)and task load(simple task and difficult task)on sEMG and dynamic stability of human lower limbs and their interactions were analyzed by two-factor repeated measures of variance.Results The AEMG of left and right biceps femoris muscles and right tibialis anterior muscle during walking with simple load were lower than those during walking with difficult load(P<0.05),and the AEMG of left tibialis anterior muscle during simple motor dualtask walking was lower than that during difficult motor dual-task walking(P<0.05).The AEMG of right gastrocnemius muscle during difficult cognitive dual-task walking was lower than that during difficult motor dualtask walking(P<0.05),the AEMG during simple cognitive dual-task walking was higher than that during difficult cognitive dual-task walking(P<0.05),and the AEMG during simple motor dual-task walking was lower than that during difficult motor dual-task walking(P<0.05).The margin of stability(MoS)of simple cognitive dual-task walking was larger than that of simple motor dual-task walking(P<0.05),the MoS of difficult cognitive dual-task walking was smaller than that of difficult motor dual-task walking(P<0.05),and the MoS of simple motor dualtask walking was smaller than that of difficult motor dual-task walking(P<0.05).Conclusions Dual tasks with different types and loads have interaction effects on dynamic posture control.The neuromuscular control around the ankle muscle and dynamic stability during difficult motor dual-task walking are better than those during difficult cognitive dual-task walking,and the neuromuscular control around the ankle muscle and dynamic stability during difficult motor dual-task walking are better than those during simple motor dual-task walking.