The main function of the three-headed shoulder joint – which runs from the clavicle and scapula down to the upper arm – is to rotate and lift the arms. The anterior (front deltoid) lifts the arms to the front, while the medial (middle deltoid) lifts the arms to the side, and posterior (rear deltoid) lifts the arms back to the rear. But while this mighty, multi-use joint is flexible – capable of assuming no less than 1,600 different positions – it’s also the reason it’s one of the most susceptible to injury during training. Because shoulder injury can happen, seemingly without cause, prevention is so much better than cure.
The shoulder may present three heads, explained above, but the joint itself actually comprises four joints:
- Sternoclavicular (SC) joint (between the sternum and the collar bone) – this is actually the only bony connection that the shoulder has with the main skeleton
- Acromioclavicular (AC) joint between the collar bone and the point of the shoulder called the acromion, which is part of the scapula or shoulder blade
- Glenohumeral (GH) joint between the glenoid part of the scapula – the socket – and the head of the humerus (HOH) – the ball
- Scapulothoracic (ST) joint (the ‘ false joint’ between the scapula and the rib cage that it rides over)
A remarkable invention, the shoulder is, until it goes wrong!
Balance – The Key To Avoiding Injury
Balance is key to injury prevention of the shoulders. And balance is achieved through five ingredients of control:
- Sports-specific technique
- Core stability
- Rotator-cuff control
- General strength
Poor performance and shoulder pain commonly originate in bad habits and faulty technique. Often these faulty methods are only revealed when muscle fatigue sets in, and injury occurs.
The purpose of flexibility varies for the different muscles around the shoulder. For the major power muscles, flexibility facilitates freedom of movement for the pelvis, trunk, scapula, and humerus. For the rotator cuff, the critical issue is balancing forces that center the head of the humerus, and whatever provides overall more freedom of movement. This is why stretching is so important.
A whole science unto itself, core training is critical for balancing the lumbar and cervical spine and the scapulothoracic joint. If these areas are not stable, extra loading and strain is passed on to the shoulder joint. This is not something often talked about in bodybuilding circles, but go to a therapist and they’ll explain that it’s a major reason for injury.
Rotator-Cuff Strength And Control
The rotator cuff is dependent on the good positioning of the scapula for effective control. If your scapula is angled too far forward or downward, for instance, rotator-cuff muscles are biomechanically disadvantaged and prime mover muscles may fail to generate enough power to be effective or avert injury.
General Muscle Strength
It’s always important to look at the big picture of the ‘outer core’ and how the condition and balance of the rest of your body influences growth and proclivity for injury.
Balance can be approached two ways: Looking at working all of the muscles evenly to avoid imbalances (one muscle bigger or more developed than another) OR the balance within a single muscle group.
It’s in looking at the balance in the shoulder, between heads and joints, that is most critical to avoiding injuries.
Most athletes believe that a gym routine needs to include strengthening work for the deltoids (three heads), latissimus dorsi, pec major, upper trapezius, and the rectus abdominis because they are the prime movers of the shoulder.
Imbalance between the front of the shoulder and the back is probably the biggest culprit to injury. Whether it’s an overuse injury an athlete carries (rear delts and super spinaetus is most usual), the point is to find the cause. In that case, it’s a case of overdeveloped pecs and lats relative to the joints of the shoulder.
To correct this, flexibility needs improving, work with a chiropractor with scapular setting and a change in the focus of exercises.
A good way to avoid shoulder injuries is to make sure your upper-body strength sessions are balanced.
Too many athletes and weight trainers focus on developing the ‘ mirror muscles’, the upper trapezius, anterior deltoid and pectorals. As a consequence, the ‘ non mirror muscles’ , lower trapezius, rhomboids, latissimus dorsi and rear deltoid are underdeveloped.
This leads to a muscular imbalance about the shoulder. Addressing this imbalance is very important for the prevention and rehabilitation of shoulder impingement injuries.