Étude des adaptations spécifiques à la pratique des activités d’armer : facteurs de risque et prévention des pathologies de l’épaule
The shoulder joint complex is largely involved in the tennis strokes. Particularly, the tennis serve applies high mechanical constraints and requires extreme joint positions making the shoulder vulnerable to injuries. Intensive tennis practice leads to musculoskeletal and functional adaptations that are thought to be beneficial to performance. However, it remains unclear when they become unbalanced or excessive that increases the risk of injury. The prospects are scouted from 5 years old, but little is known on their specific shoulder characteristics, risk factors for injury and pathomechanics. Such knowledge would be useful to optimize their monitoring by coaches. This thesis aimed to characterize the young tennis player's shoulder, identify risk factors for injury and describe the shoulder pathomechanisms related to the tennis serve. To characterize the young tennis player’s shoulder, 67 asymptomatic tennis players aged 7 to 13 years old were divided into three groups according to their biological age. The comparison between our three groups highlighted that the glenohumeral ranges of motion and the shoulder muscle strength adaptions occurred from an early age. Then to bring risk factor for shoulder injuries to light, these parameters were also compared between 31 players with a history of shoulder pain and 60 asymptomatic players. Players with a history of shoulder pain presented a larger glenohumeral joint total rotation range of motion as well as a weakness of the glenohumeral external rotator muscles and the scapular stabilizer muscles. A longitudinal study, using a latent profile transition analysis, was conducted to determine whether the factors previously identified were the cause or consequence of the shoulder injury. Furthermore, in the aim to describe the shoulder pathomechanisms related to the tennis serve motion, the glenohumeral and scapulothoracic kinematics of the tennis serve were compared between 13 players without and 15 with a history of shoulder pain. Players with a history of shoulder pain adapted their glenohumeral and scapulothoracic kinematics at the end of the cocking phase to probably preserve the sub-acromial space and the rotator cuff tendons during the tennis serve. Finally, the previous study was completed by a study analyzing the shoulder biomechanics of a tennis serve before and after the fatigue of the lower trapezius. The weakness of the scapular stabilizer muscles impaired the scapular kinematics and decreased the activation of the anterior shoulder muscles that may jeopardize the shoulder joint anatomical structures. These findings bring new knowledge to improve the young players monitoring and the injury prevention. Particularly, it highlights the importance to strengthen the stabilizer muscles (glenohumeral external rotator muscles and scapular stabilizer muscles).
tennis kinematics young muscle strength range of motion muscle activation overhead sport electromyography