基于惯性测量单元的女子速度滑冰运动员下肢运动协调特征研究

Research on Female Speed Skaters’Lower Limb Motor Coordination Based on Inertial Measurement Unit

目的:运动协调性是影响速度滑冰运动员运动表现的重要因素之一。由于缺少相关研究,目前对速度滑冰运动员下肢运动协调性特征的了解非常有限。因此,本研究目的是基于惯性测量单元分析女子速度滑冰运动员下肢运动协调性,探讨基于惯性测量单元评估下肢运动协调的可行性。方法:以7名女子速度滑冰运动员为研究对象,利用基于惯性测量单元的无线可穿戴式动作捕捉系统采集运动员在室内400 m椭圆形场地的运动学数据,采样频率为100 HZ。选择运动员在直道阶段的下肢髋、膝和踝关节角度的时间序列数据,基于向量编码技术对10个步态周期数据进行计算,通过关节间耦合角来量化下肢关节间协调性。结果:1)女子速度滑冰运动员直道阶段右腿支撑阶段占步态周期的65%,右腿摆动阶段占步态周期的35%,其中,双支撑阶段占整个步态周期的26%;2)左侧髋、膝和踝关节与右侧髋、膝和踝关节在相同时间的角度变化不同,但是,在整个时间周期的变化趋势类似;3)右侧髋-膝和膝-踝关节的耦合角度变化趋势类似,均表现出3个波峰和3个波谷;4)髋-膝关节耦合角相位频数分布方面,膝关节主导相位在支撑阶段占优,髋关节主导相位在摆动阶段占优;膝-踝关节耦合角相位频数分布方面,膝关节主导相位在支撑阶段和摆动阶段均占优。结论:基于惯性测量单元测量的数据可以较好的计算出女子速度滑冰运动员髋、膝和踝关节的运动表现特征以及运动协调特征,膝关节主导相位在下肢运动协调模式中起重要作用。

Coordination is one of the important factors affecting speed skaters’performance.Due to the lack of relevant research,the current understanding of the coordination of speed skaters’lower limbs is very limited.Therefore,this research aims to analyze female speed skaters’lower limbs motor coordination based on inertial measurement unit(IMU),and to explore the feasibility of evaluating lower limb motor coordination based on IMU.Method:this study takes 7 female speed skaters as the research subject,and collects the kinematic data of them in an indoor 400-meter oval rink using a wireless wearable motion capture system based on IMU,with a sampling frequency of 100 Hz.The time series data of the hip,knee and ankle joint angles of the skaters’lower limbs in the straight phase are selected,and the 10 gait cycle data are calculated based on the vector coding technology,and the coordination between the joints of the lower limbs is quantified by the coupling angle between the joints.Results:1)for female speed skaters,the right leg support phase accounts for 65% of the gait cycle in the straight phase,and the right leg swing phase accounts for 35% of the gait cycle.Among them,the double support phase accounts for 26% of the gait cycle;2)the angle changes of the left hip,knee,and ankle joints are different from those of the right hip,knee,and ankle in the same time period,but the trend of changes over the entire time period is similar;3)the change trend of the coupling angle of the right hip-knee and knee-ankle joints is similar,showing 3 crests and 3 troughs;4)in terms of the frequency distribution of the hip-knee coupling angle phase,the knee-dominant phase is dominant in the support stage,and the hip-dominant phase is dominant in the swing stage;in terms of the frequency distribution of the knee-ankle coupling angle phase,the knee-dominant phase is dominant in both the support stage and the swing stage.Conclusion:the motor performance and coordination features of the hip,knee and ankle of speed skaters can be better measured on the basis of IMU.The knee-dominant phase plays an important role in lower limb motor coordination.