The Biomechanical Analysis Between One-handed Backhand Stroke,Slice And Tennis Elbow Injury Of Tennis Amateurs

Object:By the biomechanical analysis of tennis amateurs' one-handed backhand stroke and slice action,this paper wants to find out the relationship between the external performance and the intrinsic nature of muscle of “tennis elbow”,and study the factors that may cause sports injury in the course of action,so as to guide tennis amateurs' stroking techniques scientifically,and provide data support for the prevention of “tennis elbow”.Methods:This paper collects collect the video and sEMG signals of the one-handed backhand stroke and slice action by adopting the synchronous method of three-dimensional high-speed camera(400Hz)and sEMG signal acquisition system(1500Hz)with nine tennis amateurs(males)aged between 35-55 years old in Liaocheng.This paper clicks 13 points including head,shoulders,right elbow,right wrist,right hand,hips and racket in Simi Motion and obtains the data of relative angle,angular velocity and angular acceleration.At the same time,related parameters such as RMS amplitude and the contribution of test muscles were calculated by using the sEMG analysis system.Results:The RMS of the muscles in the two groups showed a decreasing trend with the change of the movement stage,and the RMS of the muscles in the racquet preparing stage was the largest,basically showing a significant difference from the swing stage,the hitting stage and the follow up stage(p<0.05).In the one-handed backhand stroke and slice actions,the contribution of test muscles degree of the extensor carpi radial muscle group had significant difference in the whole movement stage,the racquet preparing stage,the swing stage,the hitting stage and the follow up stage.According to the analysis of the angle between the rocket and the forearm and elbow joint Angle,in the racquet preparing stage,the forearm in this stage changed from neutral position to pronation position,and the extensor carpi radial muscle group as the muscle that contributed the most to one-handed backhand stroke,indicating that the wrist flexion was the main posture change in theracquet preparing stage of one-handed backhand stroke.In the swing stage,the forearm was in the pronation position,and the reduction of the Angle between the rocket and the forearm was related to the dorsal extension and radial deviation of the wrist joint.According to figure 4-4A and 4-4B,the reduction range and time of the Angle between the rocket and the forearm of the one-handed backhand stroke were larger than that of the single-handed backhand slice,so the contribution of the extensor carpi radial muscle group was greater than that of the one-handed backhand slice.At the hitting stage,the elbow Angle and the Angle between the rocket and the forearm of the two movements showed an increasing trend,but the increase of the Angle between the rocket and the forearm was less than the elbow Angle.Meanwhile,the one-handed backhand stroke action should bear more external torque to maintain the stability of the wrist joint,so the contribution of test muscles of the extensor carpi radial muscle group of the one-handed backhand hitting action was greater than that of the one-handed backhand slice action.After hitting the ball,the Angle between the rocket and the forearm of the two movements increases first and then decreases.The increase amplitude of the one-handed backhand slice was greater than the one-handed backhand stroke,but the decrease amplitude was less than that of the single-handed backhand stroke.However,the contribution of test muscles of the extensor carpi radial muscle group was less than that of the one-handed backhand stroke.Therefore,the work done by the extensor carpi radial muscle group during the Angle between the rocket and the forearm increasing stage was less than that decreasing stage.Conclusions:The extensor carpi radial muscle group has a higher muscle contribution in the action of one-handed backhand stroke,and its RMS amplitude value is low,the muscle strength is weak,easy to produce sports fatigue,thus leading to "tennis elbow" injury.The middle band of deltoid muscle,biceps brachii and triceps brachii can help increase the racket speed,reduce the centrifugal contraction amplitude of the extensor carpi radial muscle group when the group is nearly fixed,stabilize the wrist joint,and reduce the gap between the external torque and the torque of the prime mover muscle,so as to effectively reduce the occurrence of injury.