前后方向水平姿势扰动对人体站立平衡响应的影响

Effects of translational perturbations with forward and backward directions on postural responses

目的:对比受试者在受到站立平台突然前移和后移两方向外部干扰下,姿势控制过程中运动学及相关肌肉动员表现,为平衡障碍人群的康复提供理论指导。方法:使用三维红外运动捕捉系统(100Hz)、无线表面肌电采集系统(4000Hz)采集13例男性青年受试者分别受到站立平台前、后两方向水平移动干扰刺激时,姿势控制过程中的肌电及运动学数据,对比研究下肢三关节及躯干的角度变化、身体质心前后方向位移及平衡恢复过程中各相关肌肉平均积分肌电值。结果:两方向水平刺激下身体质心位移方向相反,各关节表现出了方向相反的角度变化;在站立平台后移时,腓肠肌的活动强度要显著大于站立平台前移时(P<0.05),而股直肌、胫骨前肌和腰段竖脊肌的肌电活动则表现为站立平台前移时显著较大(P<0.05);除腹直肌和竖脊肌外,其他肌肉的激活时间无显著差异。结论:中枢神经系统会根据不同方向扰动自动调节人体的响应,通过协调主动肌与拮抗肌的活动强度,控制人体各主要环节的运动,从而将人体质心控制在支撑面内,维持机体的稳定。

Objective:To investigate muscle activations and the kinematics of the postural responses to external perturbations with forward and backward directions and provide theoretical guidance for the rehabilitation of patients with balance disorders.Method:Three dimensional video graphic and surface electromyography(sEMG)data were collected from13male young people,who were disturbed by forward and backward platform movements.Horizontal CoM displacement,onset latency and magnitude of muscle activations,and angular change of three lower limb joints and trunk during postural control(from onset of perturbation to200ms after perturbation)were measured.Results:The results showed that when platform moved forward or backward,CoM moved in opposite directions.The ankle,hip and trunk showed opposite angular changes.The gastrocnemius muscle had greater activation magnitude when the platform moved backward,while rectus femoris,tibialis anterior and erector spinae showed greater activation magnitude when moved forward.Except rectus abdominis and erector spinae,there was no significant difference in onset latency of other muscles between forward and backward perturbations.Conclusion:According to different directions of surface external perturbations,the central nervous system will automatically adjust postural responses by changing the pattern of joint movement and muscle recruitment to maintain body stability.