What is swimmer's shoulder?
Swimmer's shoulder is an inflammatory condition caused by the mechanical impingement of soft tissue against the coracoacromial arch. This condition is most often caused by the repetitive overhead arm motion of the freestyle stroke. The pain associated with swimmer's shoulder may be caused by two different sources of impingement in the shoulder. [Read about shoulder anatomy]
One type of impingement occurs during the pull-through phase of freestyle. The pull-through phase begins when the hand enters the water and terminates when the arm has completed pulling through the water and begins to exit the surface.
At the beginning of pull-through, termed hand-entry, if a swimmer's hand enters the water across the mid-line of her body this will place the shoulder in a position of horizontal adduction which mechanically impinges the long head of the biceps against the anterior part of the coracoacromial arch.
A second type of impingement may occur during the recovery phase of freestyle. The recovery phase is the time of the stroke cycle when the arm is exiting the water and lasts until that hand enters the water again.
As a swimmer fatigues it will become more difficult for her to lift her arm out of the water, and the muscles of the rotator cuff which work to externally rotate and depress the head of the humerus against the glenoid become less efficient.
When these muscles are not working properly the supraspinatus muscle will be mechanically impinged between the greater tuberosity of the humerus and the middle and posterior portions of the coracoacromial arch.
These two repetitive use injuries can result in painful swimmer's shoulder.
Why do swimmers get swimmer's shoulder?
Swimmers may have shoulder pain for many reasons. Poor swimming technique is a major factor in shoulder pain. As mentioned previously, if a swimmer crosses mid-line upon hand-entry, this may cause impingement of the long head of the biceps tendon.
As well, if a swimmer's hand enters the water with the thumb pointing down and the palm facing outwards, this can result in the same type of impingement.
Overtraining can lead to shoulder pain if the swimmer continues to swim with fatigued muscles. As the muscles fatigue they will work less efficiently which has two poor consequences.
First, the muscles will have to work harder in a weakened condition. Second, the swimmer will have to perform more strokes to cover the same distance, which is overusing already fatigued muscles. Together these two factors can result in swimmer's shoulder.
Unilateral breathing may also cause swimmer's shoulder. Swimmers who consistently turn their heads to the same side to breathe are risking shoulder pain in the opposite shoulder as it has to work harder to support forward movement with the head turned to the side.
Overuse of certain training equipment may cause shoulder pain. The use of hand paddles that are much larger than the swimmer's hand, or those paddles that do not have drainage holes place great strain on the shoulder muscles during the pull-through phase of freestyle. Using a kickboard with arms fully extended in front of the swimmer can place the shoulder in a position of impingement.
The longer the swimmers uses these items, or uses them incorrectly, the greater the risk of shoulder pain.
How can I prevent swimmer's shoulder?
Swimmer's shoulder can be prevented by using proper freestyle stroke. The hand should enter the water with the small finger first and the palm facing inward. When the hand enters the water it should not cross the middle of the body to avoid impingement. For further stroke instruction, seek the advice of a swimming coach.
Swimmers should avoid rapid increases in training distances or frequency of training as this is likely to wear out the shoulder muscles leaving them at risk for impingement and shoulder pain.
Stretching shoulder, chest and neck muscles will help to prevent a swimming posture that is conducive to impingement. Generally, swimmers have tight neck, chest and anterior shoulder muscles that cause them to assume a hunched over posture.
Tricep stretch: Begin by raising your arm directly over your head with your palm facing front. Bend your elbow and try to reach the shoulder blade on the same side of you body. Use your opposite arm to push your elbow back.
Doorway stretch to the pectoralis major: Begin by placing your elbow against the frame of a door. Keep the angle between your trunk and your arm at 90 deg. Rest your forearms against the door frame. Step forward with one foot to feel the stretch.
Infraspinatus stretch: Extend your arm out directly in front of you and bend your elbow across your body. With your other hand gently pull your elbow across your body.
Levator scapulae stretch: Begin by placing one arm as in the first part of the triceps stretch. Look towards your opposite hip and use you free hand to gently pull your head towards your hip.
Upper trapezius stretch: Lean your head to the side trying to bring your ear towards your shoulder without lifting your shoulder
Latissimus dorsi stretch: Raise both arms overhead and place palms together interlocking fingers. At shoulders lift arms upwards with fingers remaining intertwined.
Axial extension: Pull your chin down and backwards as if trying to make a double chin.