跑姿再训练对冲击力、下肢生物力学及刚度的影响

Effects of Gait Retraining on Impact Forces,Lower Limb Biomechanics and Leg Stiffness

目的通过建立12周跑姿再训练(gait retraining,GR)的干预模式(即通过一定的姿态目标改变跑者原有跑姿),确定GR前后跑步时垂直地面反作用力(vertical ground reaction force,v GRF)以及髋、膝、踝三关节运动学、动力学和下肢刚度特征的变化,探究跑姿转换对冲击力和下肢生物力学的影响。方法采用Vicon运动捕捉系统和Kistler三维测力台同步采集30名跑步爱好者(GR组15人,对照组15人)GR前后穿着极简鞋以12 km/h±5%速度通过测力台的GRF以及标记点轨迹。结果共17名受试者(GR组9人,对照组8人)完成训练。训练后两组最大负载率都显著下降,GR组相比对照组最大负载率更低;GR组足部触地角度显著减小,两组跖屈角度和髋关节蹬伸角速度都显著增加;GR组踝关节力矩增加;两组下肢刚度均显著增加。结论成功建立12周GR运动干预模型(前掌着地转化率为78%)。GR能有效避免冲击力峰值、降低最大负载率、提高下肢刚度,进而在减小甚至避免由冲击力引起的跑步损伤风险的同时,为提高跑步经济性提供可能。

Objective By establishing the intervention mode of 12-week gait retraining(GR)(with the specific aim of changing the habitual running gait),to determine the changes of vertical ground reaction force(vGRF),kinematics and dynamics of hip,knee,ankle joints,as well as stiffness of lower limbs in running before and after GR,and to explore the influence of running posture transformation on impact force and lower limb biomechanics.Methods Vicon motion capture system and Kistler 3D force measurement platform were used to collect the GRF and marker track of 30 runners(15 in experimental group and 15 in control group)before and after GR with the minimalist shoes at a speed of 12 km/h±5%.Results A total of 17 subjects(9 in experimental group and 8 in control group)completed the GR.After GR,the maximum loading rate of both groups decreased significantly,and the maximum loading rate of experimental group was lower than that of control group.The foot strike angle in experimental group decreased significantly after GR,and the plantarflexion angle and hip joint angular extension velocity increased in both groups.The force moment of ankle joint increased in experimental group,and the stiffness of lower limbs was significantly improved in both groups.Conclusions A 12-week GR exercise intervention model was successfully established,with 78%conversion rate(from rearfoot strike to forefoot strike).GR can effectively avoid the peak of impact force,reduce the maximum loading rate,increase the lower limb stiffness,and thus reduce or even avoid the risk of running injury caused by impact force and may provide a possibility for the improvement of running economy.