Alterations in scapulothoracic and humerothoracic kinematics during the tennis serve in adolescent players with a history of shoulder problems.

The tennis serve generates high musculoskeletal loads at the shoulder complex, making athletes particularly vulnerable to chronic injuries, especially adolescent players. Chronic injuries are commonly related to altered scapular kinematics. This study explored the effects of a history of shoulder problems involving humerothoracic and scapulothoracic kinematics during the tennis serve at low speed in adolescent competitive players with and without a history of dominant shoulder problems. Totally, 28 adolescent tennis players were split into two groups, those with and those without a history of shoulder problems. Data on humeral and scapular kinematics relative to the thorax were collected using an electromagnetic system during slow velocity serves. The two groups's humerothoracic and scapulothoracic 3D joint angles were compared both at the end of the cocking phase and at the end of the acceleration phase of the tennis serve. At the end of the cocking phase, the players with a 30 history of shoulder problems showed less humeral abduction and external rotation and more scapular upward rotation. This group also showed less humeral abduction at the end of the acceleration phase. Players with a history of shoulder problems adapted their humerothoracic and scapulothoracic orientations to preserve shoulder integrity during the tennis serve.

Shoulder range of motion and strength in young competitive tennis players with and without history of shoulder problems.

OBJECTIVE: To assess the effect of a history of shoulder problems on the shoulder flexibility and strength in young competitive tennis players. DESIGN: Cross-sectional study. PARTICIPANTS: Ninety-one competitive and asymptomatic tennis players aged between 8 and 15 years old were divided into two groups according to the presence or absence of a history of shoulder problems. OUTCOME MEASURES: Glenohumeral joint ranges of motion and the strength of eight shoulder muscles were bilaterally assessed. Five agonist/antagonist muscle strength ratios were also reported. Ranges of motion, strengths and strength ratios were bilaterally compared between the two groups. RESULTS: Players with a history of shoulder problems presented a higher total arc of rotation for both glenohumeral joints (p = 0.02) and a lower external/internal glenohumeral rotator muscle strength ratio (p = 0.02) for both sides. They also presented stronger upper trapezius (p = 0.03) and dominant serratus anterior (p = 0.008) muscles than players without a history of shoulder problems. CONCLUSION: Having a history of shoulder problems may alter the balance between mobility and stability within the shoulder complex suggesting that particular attention should be given to dominant and non-dominant shoulder functions by coaches and clinicians.