be able to effectively control the position of their scapula for optimal cuff function.
Injury prevention strategies
Most cuff injuries can be prevented relatively simply. The crucial point is not to overwork the rotator cuff by increasing shoulder work too rapidly. Keeping increases in workload to less than 10% per week will significantly reduce the risk of injury. The important balance between stability and range of shoulder movement has already been emphasised. Athletes with access to sports medicine support will benefit from a formal assessment of dynamic shoulder function.. This should encompass a comprehensive review of static and dynamic anatomy, range of motion at all four joints of the shoulder joint complex, muscle strength and balance (particularly of the rotator cuff and scapular stabilisers) and an assessment of inherent glenohumeral stability in all three planes. Significant abnormalities detected need to be address and corrected. Such screening is becoming increasingly routine for the more elite overhead athlete and validated assessment and treatment protocols have been defined. Technique should be evaluated by the coach and appropriate technical changes integrated into the rehabilitation programme.
The role of the kinetic chain
Increasingly, the role of force generation by other body components is being assessed. For instance, the power generated by the shoulder in the tennis serve has been preceded by power generated by the legs, trunk and back. The muscle mass of the shoulder is relatively small, and if inadequate power is generated by the preceding links in the kinetic chain the shoulder has to play 'catch-up' and generate power rather than acting as a force regulator. Improving the server's leg action, lumbar strength and trunk rotation during the serve will reduce the incidence of rotator-cuff injury. Such biomechanical analysis is difficult but, in skilled hands, is a crucial and effective element in injury prevention.
How can an athlete prevent injury?
Although shoulder rehabilitation protocols after injury need to address subtle muscle imbalances and joint restrictions, and thus need supervision, isolated rotator-cuff strengthening exercises can be very effective as part of a pre-participation conditioning programme and can be done using the following three simple exercises. The key is to strengthen the internal rotator (subscapularis), external rotators (infraspinatus and teres minor) and abductor (supraspinatus) muscles of the shoulder. This is most easily and safely done using the variable resistance of a cliniband - a length of flat rubber available from large chemists in varying resistances. You will need about two metres; start with the lowest resistance and work up!
To strengthen the right scapularis muscle, start by holding your right arm by the side of your body with your elbow bent/flexed at 90 degrees (the forearm will be at right angles to the upper arm and the line of the forearm points forward). Attach or loop one end of the cliniband over a door handle to the right of your body and hold the other end in your right hand. Internally rotate your humerus against the resistance of the cliniband (seen from above the forearm moves in an anti-clockwise direction towards the left) while keeping your elbow bent at 90 degrees and at the side of your body. Let your forearm return to its starting position by the pull of the cliniband in a controlled fashion.
The external rotators are strengthened by the opposite action. From the same starting position but with the cliniband looped over a door handle to your left, externally rotate your right humerus against the resistance of the cliniband (seen from above the forearm moves in a clockwise direction to the right) while the elbow is again kept to the side of the body at 90 degrees. The forearm is again allowed to return to the starting position in a controlled fashion. Single sets comprise a minute of either external or internal rotation exercises and can be repeated three to five times a day. The cliniband needs to follow you around during the day