The Biomechanics Of One-Hand Backhand Stroke Technology Related To Tennis Elbow Injury

Purpose:This study analyzed and compared the similarities and differences between tennis professional athletes and beginners by one-handed backhand stroke, and wanted to find the potential risk factors of tennis elbow related to this technology of tennis, and then provided prevention and treatment of tennis elbow injury based on biomechanics.Methods:10 male tennis professional athletes and 5 male beginners participated. The study used three-dimensional videographic analysis to record the subjects'process of one-handed backhand stroke. And sEMG electrode was also set on the subjects'forearm and uparm to get the EMG of related muscles. After analyzing and comparing the data of 3D and sEMG, the study used independent samples T-Test and Pearson correlation index to analyze the differences and correlation of those indexes.Results:The group of professional athletes (PA) had a swing-distance of 2.4±0.4m, while the group of beginners (B) of 1.9±0. lm, there was an significant difference between the two groups. The ball velocity after contacting of PA was 28.14±3.68m/s, while B was 21.00±2.36m/s, and the peak contact force of PA was about 477.23±100.49N, while B was about 330.81±45.50N, there were very significant differences between the two groups. The right shoulder angle before and after the contact of the two groups were very significantly different. During the whole process of one-handed backhand stroke, the activation orders of the 6 muscles tested of PA was:extensor carpi radialis, pronator circular muscle, flexor carpi ulnaris, brachioradialis muscle, biceps, triceps. And the orders of B was:extensor carpi radialis, flexor carpi ulnaris, pronator circular muscle, biceps, triceps, brachioradialis muscle. The correlation among the indexes showed that the swing-distance and the racket velocity before contacting were significantly related, while the racket velocity before contacting and the ball velocity after contacting were very significantly related; the IEMG of triceps during the swing process was significantly related to the ball velocity after contacting, the IEMG of pronator circular muscle during the swing process was very significantly related to the collision impulse.Conclusion:The B'technical shortage was a very important potential risk factor to the tennis elbow. The torque which made the forearm pronation was generated by the impact force, and it affected the B'forearm which kept a posture of supination a lot. This was also an important risk factor leading to tennis elbow. During the process of one-hand backhand stroke, the swing-distance, racket velocity before contacting, ball velocity after contacting, IEMG of triceps and pronator circular muscle during the process of swing were related to each other; the racket-forearm angle at the end of back swing and the peak contact force were also related. Those relationships showed that the process of tennis one-hand backhand stroke was a process which all the muscles acted coordinately. If the coordination of muscles was ruined, damages would be the results.