Title: The influence of forehand spin level on potential development of epicondylitis in experienced tennis players

Abstract

Tennis is a sport that can put remarkable stresses on the human body. One particular source of injuries in tennis players involves vibrational damage to the elbow and arm due to repetitive exposure to forces of impact when hitting the ball. Although there have been a number of biomechanical and surface electromyography studies that have investigated aspects of the tennis swing in relation to ball hitting, to date no one has looked in detail at the influence of the forehand spin level on forearm muscle activity and its potential influence on the development of the common elbow injury epicondylitis. The aetiology of epicondylitis is unknown, however, it is commonly believed to develop due to damage in the musculotendinous region of the extensor carpi radialis (ECR) muscles in the case of tennis elbow (lateral epicondylitis) and for golfer’s elbow (medial epicondylitis), the flexor carpi radialis (FCR) muscle. In this project we aimed to address the overarching hypothesis that forehands hit with different spin levels (flat, topspin and lob) have significant influence on the level of forearm muscle activity and that this may contribute to the development of epicondylitis. In order to achieve this we developed a low-cost microcontroller based wearable device that could measure the EMG activity of the forearm muscles associated with the development of elbow injuries in tennis players. This device was then tested on experienced male tennis players hitting forehand strokes under realistic tennis playing conditions. The device TRAM successfully measured the EMG activity of the forearm extensor and forearm flexor muscles under realistic tennis playing conditions for all three spin levels. We found that spin level did have a significant effect on the level of maximal forearm extensor activity in the flat stroke compared to the topspin and lob spin levels. Our results suggest that coaches could consider recommending players to hit forehands with topspin in order to potentially reduce the risk of developing lateral elbow tendinopathy.