The shoulders are the upper body’s locomotive joints – the equivalent of the hips within the lower body. Like all joints in the body, the shoulder girdle (scapula and clavicle) and the shoulder joint (glenohumeral joint consisting of the scapula and humerus) lay on a continuum where a certain degree of both mobility and stability are required. The amount of mobility and stability needed at any given moment is task dependent, for example, when attempting a hand-stand the entire shoulder complex must be very stable where both the large and smaller muscles in the area co-contract to ‘lock the shoulder complex down’. On the other hand, movements such as pulling off a t-shirt, throwing, climbing or pushing overhead require adequate ranges of mobility to perform the task efficiently.
Shoulder instability is very common and has many causes. The joint’s big advantage (mobility) is also it’s Achilles heel – shoulder instability is inherent to its structure. The shoulder joint is a shallow ball-and-socket joint that is formed by the attachment of the head of the humerus with the glenoid fossa of the scapula, while the glenoid labrum endeavors to provide increased depth to the glenoid fossa’s socket. Soft tissues like the ligaments, joint capsule and rotator cuff muscles collectively hold the shoulder joint together.
When the shoulder complex is working optimally, it provides pain-free motion. Scapular stability is also required which effectively provides a steady platform for the humerus to work off. The scapula can and should also possess mobility too, adding to the full range of motion of the shoulder complex. When the surrounding musculature are weak, they compromise scapular stability and therefore de-stabilise the entire shoulder complex.
The ‘hardware’ of the shoulder complex (boney structures) and the supporting ‘software’ (all nervous system controlled soft tissues – capsule, ligaments, tendons, muscle, fascia) offer static stability when positions need to be ‘locked in’, and dynamic stability during exercise – a kettlebell snatch represents an excellent example where both are needed. In order to ensure optimal mobility and stability of the entire shoulder complex, well-aligned posture and supportive muscular balance is required and can be developed using a number of exercises that can easily be integrated into ones daily programme using a wide variety of pieces of gym equipment.