体操跳马助跳板的动力学特征  

Kinetic characteristics of gymnastic vault springboard

作　　者：吴成亮[1,2] 郝卫亚[2] 李旭鸿 于佳彬[4] 辛振芳[5] 

机构地区：[1]重庆三峡学院体育与健康学院,重庆404100 [2]国家体育总局体育科学研究所,北京100061 [3]浙江体育科学研究所,杭州310004 [4]北京体育大学,北京100084 [5]北京理工大学,北京100081

出　　处：《医用生物力学》2013年第6期665-670,689,共7页Journal of Medical Biomechanics

基　　金：国家自然科学基金资助项目(10972062);国家体育总局体育科学研究所基本科研业务费(13-02)

摘　　要：目的对国际体操联合会指定的正式比赛用助跳板进行动力学分析,建立监测跳马踏板相互作用力的新方法,为诊断踏板技术提供科学的理论依据。方法应用材料力学理论推导GYMNOVA软、硬两种助跳板弹簧弹性系数,并对助跳板进行静力学、动力学测试和计算机仿真实验验证。静力学测试:采用成90°夹角的2台摄像机,对助跳板在160、180、210和230 kg重物作用下的变形进行拍摄,采样频率600 Hz;动力学测试:1名受试者从高为1.25 m的平台上分别对两种助跳板进行落地反跳(drop jump,DJ)实验,1台摄像机对DJ动作进行拍摄,采样频率300 Hz,助跳板变形情况拍摄与静力学测试方法相同。3台摄像机都用二维框架标定,由SIMI MOTION软件解析获得助跳板不同载荷条件下的高度和速度变化以及DJ实验中人体重心的垂直加速度变化。计算机仿真:对动力学测试中助跳板DJ实验进行计算机建模与仿真。结果获得两种助跳板力—位移方程F=kx+cx。静力学实验时不同重物作用下助跳板下压高度与方程计算值相近。采用力—位移方程所得DJ过程中踏板垂直反作用力曲线与通过人体重心加速度获得的踏板垂直反作用力曲线高度相关,复相关系数>0.86。结论建立了基于高速摄像获得助跳板下压高度和速度的踏板垂直反作用力的测量方法,该方法可快速简便地监测跳马踏板过程中运动员与助跳板相互作用力,为跳马技术动作科学保障提供新手段,对跳马运动损伤预防具有积极作用。Objective To analyze the dynamics of vault springboard designated to using in formal competitions by the Federation International de Gymnastique （FIG）, and find a new method measuring the reaction force of the springboard, so as to provide scientific supports for diagnosis of its take-off technique. Methods The stiffness values of GYMNOVA soft and hard springboards were derived by method of material mechanics, then the springboards were then tested with static, dynamic experiments and computer simulations. In the static experiment, two video cameras with the sample frequency of 600 Hz were placed at a 90° angle to capture the deformation of the springboards under the loads of 160, 180, 210 and 230 kg, respectively. In the dynamic experiment, a volunteer performed drop jump （DJ） from a 1.25 m high platform onto the hard and soft springboards, respectively, while a camera was employed to capture the deformation at the sample frequency of 300 Hz. All the three cameras were calibrated using a 2-dimensional framework, and the changes of the board height, velocity under different loads and acceleration of center of mass （COM） of the human body in DJ experiment were all obtained by digitizing the videos using SIMI MOTION software. Finally, modeling and computer simulation were performed to simulate the DJ in the dynamic experiment. Results The equation F=kx＋c describing force-displacement of both the springboard was obtained. The depressing displacements of the board under different loads in the static experiment were close to those calculated by the equation. The vertical reaction force curve in DJ calculated by the equation was highly correlated to that obtained by acceleration of COM. The coefficient of multiple correlation was all greater than 0.86. Conclusions The study developed a new method for measuring the vertical reaction force of the springboard based on board depressing displacement and velocity with the help of high-speed camera. This method, which can be employed with convenience to rapidly

关 键 词：跳马 落地反跳 助跳板 动力学 仿真 

分 类 号：R318.01[医药卫生—生物医学工程]