The cause of injury

If preventing injuries is so important, then we need to be able to recognise what causes them. We generally distinguish between extrinsic causes (playing habits, training load, and game duration) and intrinsic causes (the player's anatomy, biomechanics, history of injury, etc.). However, our understanding of many of these risk factors remains speculative, since scientific evidence is still lacking.

Among intrinsic causes of injury, Bénédicte Forthomme focused on three of the shoulder’s main characteristics. Given the nature of the specialised movement, the first problem relates to the abnormal placement of the scapula on the thorax. This malposition (called dyskinesis) at rest and during arm movements can be observed during a clinical exam of the patient's back. This can become a problem for the athlete when they cock their arm and then hit the ball, for the scapula doesn't follow the humerus as it should, which increases the difficulty of the movement.

The second characteristic that could lead to injury is a muscular imbalance in the shoulder. The rotator cuffs (which surround the scapula and the humeral head) are the muscles that are most solicited during the cocking and hitting movements. The anterior muscles are strengthened through the repetition of the movement during games and by targeted training ("to hit hard"). But this is not true of their antagonists, the posterior muscles. "In the absence of correction during training, there is a risk of imbalance that can contribute to humeral head and scapular malposition, which can cause movement dysfunction," cautions the physiotherapist.

Lastly, the third source of injury is related to modifications in humeral head mobility in relation to the scapula. "When the athlete attempts to bring their hand far behind them before hitting the ball, they are encouraging hypermobility in the external shoulder rotation. They then bring their hand forward to hit the ball, and must decelerate during follow-through. The decelerating function played by certain muscles can lead to stiffness, and then a loss of mobility during the shoulder's internal rotation, which can lead to injury," she explains.

First step: measuring

"During the study, our first objective was to observe these three characteristics and measure them," says Bénédicte Forthomme. “When we understand what causes an injury, we can then develop a preventative strategy and/or appropriate treatment. The first priority is therefore to prevent problems, and if that isn’t possible, then to treat them by figuring out what we can improve. Unfortunately, current research (which is strongly lacking in the field) identifies specific adaptations that don’t actually help us clearly understand what actually causes the injury.”

A prospective study is the only way to demonstrate what really causes injuries among players. Therefore Bénédicte Forthomme and her team conducted such a study on "high-level" French players, during which they established individual profiles of each player at the beginning of the season.