体操自由操落地双侧下肢生物力学对称性研究

A phantom study on the biomechanical symmetry of lower limbs during floor landings in gymnastics

创建19环节三维多刚体模型调查体操自由操落地双侧下肢生物力学对称性。采用运动学(三维运动捕捉、高速摄像)和动力学(三维测力平台)方法采集40 cm和80 cm高度自由落地动作,获得下肢关节角度和地面反作用力,用于验证所创建的三维多刚体模型。然后使用高速摄像系统采集体操团身后空翻一周(后团)落地动作,数字化解析获得运动学数据,驱动三维多刚体模型完成计算机仿真,计算双侧下肢动力学参数。对比实验测量,模型仿真获得的地面反作用力峰值最大差值为3.8%,运动学和动力学复相关系数为0.92~0.97。尽管体操运动员采用双脚同时落地方式,下肢关节运动学角度呈现相似性,但两侧下肢动力学参数,如水平地面反作用力、下肢关节力矩、关节肌肉做功等呈现明显的不对称性。所创建的19环节三维多刚体模型可用于调查确定体操自由操落地下肢生物力学特征;体操运动员下肢动力学特征呈现非对称性;双侧不对称的动力学参数可能是体操落地下肢高损伤率的重要因素。

To develop a three-dimensional multi-body model with 19 segments to simulate and investigate the biomechanical symmetry of lower limbs and injury risk during gymnastic floor landings.In the first step,kinematic and kinetic data(the angle of lower joints and ground reaction force)measured by motion analysis and force plate of a drop landing with 40 and 80 cm height for a non-gymnast were recorded and used for validating and evaluating the developed three-dimensional multi-body model.Then kinematic data of a gymnastic floor landing of back tuck somersault captured by video were used to drive the developed model in the multi-body simulation to simulate the gymnastic floor landing.The kinetic data were calculated at last.Compared with the real kinematic and kinetic data measured by instrumentation,a maximum deviation was 3.8%for the peaks of ground reaction force and the coefficient of multiple correlation of kinematics and kinetics was between 0.92 and 0.97,which indicated the validity of the proposed model.Although a gymnast tried his best to land on both feet at the same time,the joint angles of two lower limbs was closer to each,and obvious asymmetric kinetics,such as the horizontal ground reaction forces,power,work and joint moments both in sagittal and frontal planes of two lower limbs were showed along with the bilateral analyses afforded.These findings suggest that the developed 3 D model is suitable for addressing an injury context during gymnastic floor landing.There is obvious asymmetry in kinetics of a gymnast’s lower limbs.The imbalanced loading of both lower limbs may be a key injury risk factor of gymnasts.