The gleno-humeral joint (made up of the upper arm & shoulder socket) is the most mobile joint in the body. There are less bony constrictions around this joint compared with our other joints which allows for a larger range of movement but reduced stability. The stability is provided by various ligaments around the shoulder but principally by muscles along with the shoulder blade (scapula) that provides a base of support.
The muscles around the shoulder can be categorised into type depending on their role & position in relation to the joint.
- Local Stabilisers are closest to the joint & provide feedback about the position of the joint & range of movement. Dysfunction of these muscles can be caused by pain or high load, too much or too little recruitment in a movement or delayed timing. To retrain these muscles you can challenge the balance, use low load closed kinetic chain exercises (where the hand is in a fixed space & cannot move i.e. in contact with the ground), or small range of movement exercises which are pain free. Examples of these muscles are the rotator cuff group.
- Global Stabilisers are postural muscles which control the joint throughout the range of movement especially the inner & outer ranges & generate forces to control this range of movement. Dysfunction of these muscles causes lack of control of the movement of the joint, decreased force & potentially shaking when performing an exercise or movement. Again training for these muscles should involve closed kinetic chain exercises, low loads & proprioceptive (balance challenge). This can involve the use of props such as a BOSU or Swiss ball. Examples of these muscles are the deltoid group & the upper/middle trapezius.
- Global Mobilisers normally span more than one joint (for example the biceps which works over the shoulder & elbow joints), are the prime mover muscles & produce rapid force. Tightness & over-activity (such as spasm) can cause issues with these muscles.To train these we need to use high speed & force, co-ordination & open kinetic chain (where the hand is free to move) exercises. Examples of these muscles are the biceps & pec major.
All of these muscles need to work together efficiently in order to perform movement pain free. Both Pilates & Sports Therapy sessions can help to maintain or improve flexibility, strength, balance of the muscles in relation to each other & general fitness. They can also rehabilitate you to normal daily or sporting activities & assess & correct any causative factors to decrease the likelihood of recurrence of injury or reduced function.
