Shouldering the pain of throwing

Andrew Leipus in Cricinfo

Able to bowl but not throw because of shoulder pain? Or maybe you have lost power in your throw? Have to throw side-arm? Does your whole arm go "dead" for a few seconds after you release the ball? Or you are now experiencing a click, crunch or clunk when you lift the arm? These are just some of the many symptoms and behaviours that can be present in the cricketer's shoulder and which can help clinicians diagnose what your underlying problem might be. 

There can't be a shoulder discussion without a brief anatomy lesson. In terms of understanding the basics, the glenohumeral joint is a shallow ball-and-socket design, allowing a huge amount of mobility yet remaining as stable as possible. It also has to tolerate massive torques or rotational forces generated. Some people equate the head of the humerus (HOH) and its relation to the scapula with a golf ball sitting on a tee, i.e. easy to topple over. But it is actually more like trying to balance a soccer ball on your forehead, with both the ball and the head/body constantly moving to maintain "balance" and stop the ball from dropping off. It is this balance between the socket joint and the scapula position which we need to consider in the cricketer's shoulder as it is where a lot of problems begin and where a lot of rehab programmes fail.

As is the case with all injuries, the anatomy often lets us down by not being able to cope with the functional demands. Some injuries develop acutely, such as occurs with one hard throw when off balance, and some develop over a period of time through lots of high repetition - degenerative type injuries. The two most commonly injured structures in cricket are the infamous rotator cuff and the glenoid labrum.

The cuff is a group of small muscles acting primarily to pull and hold the HOH into its glenoid socket. The long head of biceps tendon assists the rotator cuff in this role. The labrum is a circular cartilage structure designed to "cup" or deepen this socket and provide attachment for the biceps tendon.

An injury to the labrum results in the HOH having excess translatory motion and not staying centred in the glenoid. The cuff then has to work harder to compensate for this structural instability. This translation often results in a "clunky" shoulder or one which goes "dead" when called upon to throw at pace. Anil Kumble's shoulder had a damaged labrum due to his high-arm legspin action. Years of repetitive stress had detached his labrum from the glenoid, resulting in the need for surgery. He's not alone. Muttiah Muralitharan and Shane Warne also had shoulder surgeries in their careers. And it's not just spin bowling, as many labral compression injuries occur during fielding when diving onto an outstretched arm.

Injury to the cuff, however, also results in a dynamic instability, whereby the HOH is again not held centred, and subsequently over time stresses both the labrum and cuff. Impingement is a common term used to describe a narrowing of the space in the shoulder that can result from this loss of centering. The cuff doesn't actually need to be injured for this to occur - repetitive throwing can tighten the posterior cuff muscles and effectively "squeeze" the HOH out of its normal centre of rotation in the glenoid. It really is a vicious circle and cricketers compound any underlying dysfunction by the repetitive nature of the game. They might not throw much in a match but when they do it is usually with great speed. The bulk of the throwing volume occurs during their practice sessions.

And when talking about shoulder mechanics we need to also understand critical role of the scapula. In order to ensure that the HOH remains remain centred in the glenoid, the scapula must slide and rotate appropriately around the chest wall (that soccer ball example). Any dysfunction in scapula movement is typically evidenced by a "winging" motion when the arm is elevated or by observing the posture of the upper back. Whether the winging comes before the injury or as a consequence is hotly debated. Either way it needs to function properly. And to complicate things even further, the thoracic spine also needs to be able to extend and rotate fully to allow the scapula to move. Kyphotic or slouched upper backs are terrible for allowing the arm to reach full elevation and is a big contributor to shoulder problems.

It should be clear that in order for a cricketer's shoulder to be pain-free, there needs to be a lot of dynamic strength and mobility of the upper trunk and shoulder girdle. But throwing technique is equally critical to both performance and injury prevention. Studies have shown that the shoulder itself contributes only 25% to the release speed of the ball. To impart this 25%, the angular velocity of the joint can reach 7000 degrees per second. However, what is interesting is that a whopping 50% is contributed by the hips and trunk when the player is in a good position for the throw (allowing for a coordinated weight transfer). But when off-balance and shying at the stumps, as often occurs within the 30-yard circle, the shoulder alone can be called upon to produce more than its usual load. Thus it is important to remember that throwing should be considered as a whole body skill.

	Injury to the deep joint capsule ligaments and biceps tendon are difficult to diagnose but can account for that "problem" shoulder © Getty Images Enlarge

Often a player will be able to bowl without experiencing symptoms, but will struggle to throw. In these cases, it is common to find pathology involving the long head of biceps or where it anchors superiorly onto the labrum. The latter is also commonly known as a SLAP lesion. In the transition from the cocking to acceleration phase of throwing, the shoulder is forcefully externally rotated. The biceps is significantly involved in stabilising the HOH at this point and often pulls so hard that it peels the labrum off the glenoid, giving symptoms of pain and instability. The overhead bowling action, however, does not put the shoulder into extremes of external rotation and hence symptoms do not usually occur. If pain is experienced during the release phase of throwing then there is a good chance that technique is again at fault. In order to decelerate the arm after the ball is released, the trunk and arm need to "follow through", using the big trunk muscles and weight shift towards the target. Failure to do this results in a massive eccentric load on the biceps tendon, also potentially tugging on its anchor on the glenoid. Throwing side-arm to avoid extremes of external rotation and pain is a common sign that all is not well internally.

As you can see, an injury to the shoulder is not a simple problem. And there are many other types of pathology found. It requires thorough assessment and management of a host of potential contributing factors which are mostly modifiable when identified. And whilst a lot can go wrong in a cricketer's shoulder, there is a lot that can be done to make sure it stays strong and healthy. Because prevention is always better than surgery in terms of outcomes, next week I'll discuss some shoulder training and injury prevention tips used by elite cricketers.