A keen gym-goer will stereotypically work on the muscles that can be seen easily - the deltoids, rhomboids and pecs are particular favourites. Most weight enthusiasts will also include some external and internal rotation exercises to strengthen the rotator cuff.
Muscles that tend to be forgotten are the serratus anterior and lower fibres of trapezius. These muscles promote shoulder stability and the smooth gliding of the shoulder blade that is essential for any functional shoulder exercise.
Over-dominance of the pecs, deltoid and rhomboids can encourage dysfunctional shoulder blade movement which places additional shearing forces through the shoulder joint and the supraspinatus muscle (one of the rotator cuff muscles).
The supraspinatus sits between a projection on the top of the shoulder blade (the acromuim) and the humeral head (ball joint) and is prone to ‘scuffing’ or injury when the shoulder blade fails to move in-sync with the ball and socket joint as the arm lifts and lowers.
A working example of the this is the chest press exercise. During the lowering phase of the chest press the shoulder blade must inwardly rotate and stabilise the shoulder joint to prevent any excessive shearing forces going through the supraspinatus muscle. If it does not do this effectively the supraspinatus tendon becomes overloaded and experiences high shearing forces which can cause long-lasting damage.
The chest press exercise is one of the most provocative exercises you can do in the gym and any pain in the shoulder when completing this exercise should be taken as a warning that there may be excessive load through the suprasinatus tendon or surrounding structures.
If you experience pain during or after gym activities consult a physiotherapist or exercise specialist.
If your shoulders are pain free but you would like to incorporate more shoulder blade stability exercises in to your routine consider the following exercises for the serratus anterior and lower fibres of trapezius muscles:
Serratus Anterior Exercises:
1. Push-up plus
2. Boxing drills
3. Shoulder protraction and retraction using a lat pull-down machine.
Lower fibres of trapezius:
1. Prone arm extensions.
2. Scapular setting
Written By: Leanne O’Brien, Specialist Musculoskeletal Physiotherapist