双腿着地时姿势偏移对下肢各关节缓冲分配和各肌群收缩模式的影响

Influence of Postural Deviation on the Joints Cushioning Distribution and Contraction Pattern of the Lower Limb Muscles during Feet Landing

目的:研究双腿落地过程中姿势偏移对人体下肢髋膝踝关节缓冲分配及下肢肌群收缩模式的影响。方法:随机选取16名运动训练专业男性大学生完成3种姿势偏移跳深动作,同步采集分析双腿着地阶段髋中心点位移(DOHC)、下肢运动学和肌电图等特征的差异。结果:(1)前倾和后倾姿势着地缓冲阶段,髋中心点DOHC前后和DOHC左右位移分量,a前后和a左右加速度分量以及踝关节背屈ωmax均大于正常姿势(P<0.05);(2)3种姿势落地缓冲阶段,下肢各肌群标准化maxEMGRMS值均是股直肌、股外侧肌、股内侧肌和胫骨前肌最大;(3)前倾和后倾姿势的臀中肌、股直肌、股内侧肌、股外侧肌、股二头肌和胫骨前肌标准化maxEMGRMS,以及踝关节与髋关节肌肉共激活水平与正常姿势相比存在显著性差异(P<0.05);(4)习惯性腿的踝关节Δθ、ωmax和肌肉共激活水平以及外侧腓肠肌的标准化maxEMGRMS均显著大于非习惯性腿(P<0.01);(5)腾空阶段预先被激活和在缓冲阶段先达到maxEMGRMS值的均是臀中肌、臀大肌和股直肌。结论:落地前姿势偏移,人体为了避免损伤可能存在一种动作控制前馈机制,在腾空阶段预先激活近端核心肌群稳定髋关节,在缓冲阶段重新分配下肢髋膝踝关节屈曲程度,以及调节髋与膝关节屈伸肌共激活程度来实现落地动态姿势稳态。

Objective:This study was to investigate the effects of postural deviation on the flexion distribution of the hip,knee and ankle joints and the contrac⁃tion pattern of the muscles of the lower limbs during the feet landing.Methods:16 male college students majoring in sports training were randomly involved in feet landing test with three different postural deviation,displacement of the hip center(DOHC),3D joint kinematics,electromyographic signals were collected and analyzed.Result:(1)Compare the normal posture,The DOHC before-after and DOHC right-left components of DOHC,the abefore-after and aright-left components of the hip center and angular max velocity(ωmax)of ankle dorsiflexion of the forward and backward postures were significantly higher in buffer phase(P<0.05);(2)In each posture,the larger standardized maxEMGRMS of all muscles in the buffer phase were the rectus femoris,lateral femoris,medial femoris and anterior tibia(.3)The standardized maxEMGRMS of gluteus medius,rectus femoris,medial femoris,lateral femoris,biceps femoris and anterior tib⁃ial muscles and the co-activation of ankle and hip muscles of the forward and backward postures were significantly different from the normal posture(P<0.05);(4)Compare to non-dominant leg,theΔθ,ωmax and lateral gastrocnemius maxEMGRMS were larger in dominant leg;(5)The gluteus medius,gluteus maxi⁃mus and rectus femoris muscles were pre-contracting first in flight phase and also reached maxEMGRMS first in buffer phase.Conclusions:When landing with postural deviation,for avoid injury,the human body may have a motion control feedforward mechanism,pre-activate the proximal core muscles to stable hip in the flight phase,the degree of flexion of hip,knee and ankle joints were redistributed during the buffer phase and regulate co-activation of flexor extensor mus⁃cles of the hip and knee to achieve the landing dynamic postural stability.