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目的从运动学角度分析投弹运动的基本规律,探讨发生肱骨螺旋形骨折的力学机制和预防要点。方法训练现场测试采用常速摄像机定点、定焦,正侧面拍摄30名士兵的投弹动作,采用爱捷人体解析系统处理;6名士兵在肢体14个相关点贴敷反光标记,在实验室进一步测试,采用运动分析仪测定投弹运动全过程的姿态及各关节点速度峰值时的手臂角、肩臂角、躯干上臂夹角等,数据处理用Kintrak软件完成。结果30名士兵弹体最大和最小出手速度分别为14.776～9.285m/s[(12.23±1.36)m/s];并给出了肩、肘、腕速度峰值的两类情况。记录了从引臂-加速-投弹出手的运动全过程,腕关节加速度最大时和前臂与X方向夹角加速度最大时,躯干上臂夹角均值分别为90.2°、99.1°,而此时手臂角均值分别为80.2°、95.2°,肩臂角均在160°。结论投弹应以肩关节为主要转动中心,上臂带动前臂从肩上方运动,速度由肩-肘-腕依次达到最大值,既可得到最大出手速度,也可避免不必要的损伤。投掷臂从肩侧“撇弹”是易发肱骨骨折的危险动作,应特别强调加以避免。
Objective To analyze the basic rules of the projectile movement from the perspective of kinematics and to discuss the mechanics and prevention points of the humeral fractures. Methods Training site test using constant speed camera fixed-point, fixed focus, is shooting 30 side frontal bombing action, the use of Acer human body analytical system processing; 6 soldiers in the limbs 14 affixed reflective signs, in the laboratory for further testing The kinematic analyzer was used to measure the whole process of the projectile movement and the angle of the arm, the arm and the arm, the angle between the upper arm and the arm, and the data was processed by Kintrak software. Results The maximum and minimum attack velocities of 30 soldiers were 14.776 ~ 9.285 m / s [(12.23 ± 1.36) m / s] respectively. Two kinds of situations of peak of shoulder, elbow and wrist velocity were given. Recorded the whole course of the movement from the lead arm to the acceleration to the throwing hand. When the acceleration of the wrist is the maximum and the acceleration between the forearm and the X direction is the maximum, the mean included angles of the upper trunk are 90.2 ° and 99.1 °, respectively. At this moment, Respectively 80.2 °, 95.2 °, shoulder arm angle at 160 °. Conclusion Shoulder joint should be the main center of rotation. The upper arm drives the forearm to move from shoulder to shoulder. The speed reaches the maximum value from shoulder to elbow and wrist, which can not only get the maximum speed but also avoid unnecessary damage. Thigh arm from the shoulder “skimming” is a dangerous move prone humerus fractures, with special emphasis should be avoided.