The tennis serve is an extremely complex motion, which utilizes the body’s full kinetic chain. The entire service motion, from bouncing the ball to the follow-through, is of the utmost importance in which all of the sequential and coordinated actions need to be analyzed. One must take into consideration the motion before ball contact, at ball contact, and after ball contact.
In order to get to the ever-important contact point, from a biomechanical standpoint, the scapulothoracic articulation (STA) performs a beautiful dance as it goes through numerous motions in different planes. These motions occur with the scapula moving on the thoracic spine, but also, with the thoracic spine moving about the scapula. From a rehabilitation or strength and conditioning point of view, this needs to be addressed.
First of all, does the athlete possess the motor control and coordination to move the scapula independently over the thoracic spine? Secondly, does the athlete possess the motor control and coordination to move the thoracic spine about the scapula? The athlete should have the ability to dissociate the articulation with both types of movement.
Most of the exercises that I see being prescribed or performed by tennis players, including many top 100 world ranked players, focus on the scapula moving about the thoracic spine, ie. reverse fly, prone 1-arm trap raise, etc., but not the motion of the thoracic spine moving about the scapula. During the cocking stage (stages according to Kovacs and Ellenbecker, 2011), there is an acceleration of the thoracic spine about the scapula. This motion calls for exercises focusing on the dissociation of the STA with the thoracic spine moving about the scapula. An example of such an exercise can be found here.
Remember, when dealing with athletes, one must be aware and have knowledge of the sport that they are dealing with. Having this knowledge allows for the practitioner or strength coach to prescribe more robust exercises related to the sports biodynamics.