With ninety percent of the driving forces coming from the upper body, it is little surprise that swimmer’s shoulder is a common condition in swimming. The shoulder is a complex joint, and as swimming placed it under load, an appreciation of its function and limitations can help keep the body injury free. This is especially true for those who swim very regularly or have poor stroke technique, as they are most at risk.
Shoulder mobility as a strength and a weakness
Compared to other joints in the body, the shoulders and hips have an unparalleled range of motion. This is due both of them having ball and socket joints capable of a 360 degree conical movement. However, stability for each of these joints differs. The hip joint fits snugly like a ball in a glove, as the rounded head of the thigh bone, fits into the deep, cup shaped socket of the pelvis. Unlike the hip, the shoulder has a small flat socket about half the size of the ball, along with several other bones, plus a collection of muscles and tendons that support this wide range of motion. Although one of the largest and most complex joints in the body, its unique structure is also a weakness, as the shoulder accounts for up to 20% of all athletic injuries and is the most commonly dislocated joint in the body.
This balance between shoulder mobility and stability is put to the test during sports that require overhead motion. Racket sports such as tennis, or throwing sports like volleyball require two or three patterns of overhead movement. Swimming however, requires multiple overhead movement patterns and a steady conical 360 degree motion of the humerus, the bone of the upper arm. This bone fits into a socket of the scapula, more commonly known as the shoulder blade, which has a cuff of cartilage called the labrum. This ring of rubbery tissue helps keep the ball like head of the humerus in place.
As the humerus fits loosely into the shoulder joint compared to the hip, a collection of muscles and tendons known as the rotator cuff, provide support for raising and rotating the arm. To further aid fluid motion there is a small sac of fluid called a bursa that protects and cushions the rotator cuff tendons. It lies between the rotator cuff and the roof of the shoulder blade, which has two bony projections, the coracoid process and the acromion, which is above the bursa and attaches to the clavicle. Otherwise known as the collar bone, the clavicle, makes up one of three bones of the shoulder, the other two being the previously mentioned humerus and scapula. These three bones are connected to the shoulder by four joints, one being the ball and socket joint of the humerus and scapula, one for where the scapula meets the ribs at the back, and two for the clavicle which joins the scapula at one end and the chest bone at the other.
All of these structures have the potential to be injured, and as such swimmer’s shoulder can derive from a variety of sources. An appreciation of the forces at work upon the body during swimming, can provide a greater understanding of the root cause of swimmer’s shoulder.
The sources of swimmer’s shoulder
Good swimming technique requires a greater range of motion and flexibility of the shoulder compared to other sports and plays a major role in the upper body’s ability to provide locomotion. This placing of the shoulder under load, is further increased since swimming is performed in a fluid medium. As opposed to air, water creates greater resistance and forces upon the structures of the shoulder.
In one study, two thirds of the elite swimmers reported shoulder pain. In some cases swimmer’s shoulder can involve irritation to the tendons of the rotator cuff muscles, but it can also be due a range of painful shoulder overuse injuries such as impingement. This is where the shoulder blade’s bony point that joins with the collar bone, rubs on the rotor cuff and bursa. This can then lead to inflammation of the bursa, known as bursitis, or tendonitis.
The four tendons that make up the rotator cuff and one of the bicep tendons are most commonly affected by tendonitis, once again as a result of wear. Like with any other joint in the body, the ligaments, tendons, and muscles around the shoulder can tear or become loose. This can lead to instability in the shoulder and the chance of greater injury, such as a tear to the the ring of cartilage that holds the humerus in place, or dislocation. Also these areas can be affected by chronic conditions such as osteoarthritis.
The repeated overhead motion of the arm in swimming and pressures placed upon the shoulder joints in water, mean that immediate care of a newly acquired injury and preventative measures are essential. Seeking physiotherapy treatment can identify the exact area of injury, alleviate pain and then planning can be put into place to regain stability, strength and flexibility. For example a gym program with some simple strength and flexibility exercises can be easily prescribed. Through future self management of the swimmer’s shoulder condition there lies the opportunity to proactively train the body so as to minimise the risk of injury.
Managing shoulder health
First of all as with any inflammation injury, the PRICE principle should be applied to the shoulder. This is achieved by protecting the injured area, resting the shoulder, applying ice for 15-20 minutes every two to three hours, compression with a bandage and elevation of the arm above the level of the heart.
Once the area has recovered due to rest or treatment by a physiotherapist, and a strengthening plan has been devised for the injured area and surrounding structures, then it is time to venture back into the water. At this point advice from your physiotherapist, doctor should be taken and the help of a qualified swimming professional or experienced swimmer could ease the transition back to the pool.
After all investigating and understanding proper swimming stroke technique, could prevent a relapse of injury and aid in the rehabilitation of an recovered shoulder. It is also important to know the limits that a recovering shoulder can take, being sure to train conservatively so as to avoid tired muscles. This is also true for those who are injury free, as training at a limit within the body’s fitness level will maintain stability of the shoulder and aid correct function.
Prevention through correct technique
Swimmer’s shoulder can develop with all styles of swimming, with freestyle, backstroke and butterfly seen to be the most responsible for injury, as the arms circle overhead. Although the most gentle looking, breast stroke still places pressure on other parts of the body, and like the other styles, requires good technique to avoid injury. So an option could be to vary the types of swim stroke performed, as this can provide rest and recovery to muscles, joints and tendons that would otherwise be overworked. Refining the technique and building the strength of each swimming stroke style can also avoid other swimming conditions that effect the knees, neck and lower back.
In general terms there are four areas of swimming technique that can aid protection against shoulder injury. As with land based activities, good posture is essential, so keeping the shoulders back and the chest forward will help. Next is developing symmetrical body rotation, that is encouraged by a balanced left and right breathing pattern. This allows for better support to the rotator cuff and generates more power by engaging the muscles of the back and core.
Regarding the best practice for stroke technique, hand placement as the arm enters the water and the shape of the arm when pulling through the water, are also essential in injury avoidance. It is best to have a flat hand as it enters the water at the start of a stroke. This is fingertips first, rather than thumb whereby the arm is rotated outwards. Lastly as the hand then catches the water and pulls through, the elbow should be high so that the water is pushed back, rather than down when the elbow is dropped or the arm is very straight.