步频差异对大学生跑步时下肢冲击力和运动学特征的影响研究

Influence of step frequency difference on the impact force and kinematic characteristics of lower limbs of college students during running

目的对比以同一速度不同步频进行跑步时,步频的改变对大学生下肢冲击力和运动学参数的影响,为大学生合理的制定跑步计划提供参考。方法随机选取了15名体育专业的男性大学生,让其分别以高步频(190步/min)、中步频(170步/min)、低步频(150步/min)在跑步机上以同一速度(9 km/h)进行跑步。采用1000 Hz的三维测力台和200 Hz的红外动作捕捉系统分别对对受试者跑步过程中下肢受到的冲击力和下肢各关节的运动学参数进行采集。结果随着步频增加,受试者的垂直地面作用力的第一峰值力和第二峰值力均逐渐降低,具有显著性差异(P<0.05);冲击负载率出现的第一峰值及第二峰值均逐渐降低,具有极显著性差异(P<0.01)。着地时刻膝关节力矩随步频增加而降低,踝关节力矩和髋关节力矩随步频增加而增大(P<0.05);离地时刻膝关节力矩和髋关节力矩随步频增加均无较显著变化(P>0.05)。着地时刻下肢踝关节角度逐渐减小,膝关节角度逐渐增大,髋关节的屈伸和内收外展角度逐渐增加,具有显著性差异(P<0.05);离地时刻踝关节内翻外翻、内旋外旋角度逐渐减小,膝关节被动内收外展角度逐渐增大,髋关节内旋外旋角度逐渐降低,具有显著性差异(P<0.05)。支撑时期踝关节、膝关节活动幅度均逐渐减小,具有显著性差异(P<0.05)。结论适当增加步频有助于减少下肢冲击力和能量损失,降低运动损伤风险,并改善跑步过程中的运动学参数,提高跑步的效率和舒适度。

Objective To compare the influence of step frequency change on the impact force and kinematic parameters of lower limbs of college students when running at the same speed and with different step frequency so as to provide reference for college students to make a reasonable running plan.Methods In this study,15 male college students majoring in physical education were randomly selected to run at the same speed(9 km/h)on a treadmill at high step frequency(190 steps/min),medium step frequency(170 steps/min),and low step frequency(150 steps/min),respectively.A 1000 Hz three-dimensional force measuring table and a 200 Hz infrared motion capture system were used to collect the impact force on the lower limbs and kinematic parameters of each joint of the lower limbs during the running process.Results With the increase of step frequency,the first and second peak forces of the subjects'vertical ground force decreased gradually,with significant differences(P<0.05).The first peak value and the second peak value of impact load ratio decreased gradually,and there was a very significant difference(P<0.01).At the moment of landing,the knee joint torque decreased with the increase of step frequency,and the moment of ankle joint and hip joint increased with the increase of step frequency(P<0.05).However,the knee joint torque and hip joint torque did not change significantly with the increase of step frequency(P>0.05).At the moment of landing,the angle of ankle joint decreased gradually while the angle of knee joint increased gradually,and the angle of flexion extension and adduction and abduction of hip joint increased gradually,with significant differences(P<0.05).At the time of lifting off the ground,the angle of ankle inversion and ectropion and internal and external rotation gradually decreased,the passive adduction and abduction angle of knee joint gradually increased,and the angle of internal and external rotation of hip joint gradually decreased,with significant differences(P<0.05).During the period of support,the movement amplitude of ankle joint and knee joint decreased gradually,with a significant difference(P<0.05).Conclusion Appropriate increase of step frequency is helpful for reducing the impact force and energy loss of lower limbs,reducing the risk of sports-induced injury,improving the kinematic parameters during running,and improving the efficiency and comfort of running.