As the summer approaches and schools let out, more adults and children spend time at the pool. Participation in summer swim teams and recreational swimming outside are popular activities in the summer!
If you plan on swimming more this summer, it is important to understand the biomechanics of swimming. Knowing and understanding the biomechanics of swimming will decrease the amount of injuries and make swimming more efficient for the participant.
Biomechanics of Swimming:
In order to swim, you must use your upper and lower limbs to move you through the water. About 90% of propulsion is generated by the upper limbs. The forward movement your body generates has to overcome the drag force of the water. It is important to maintain a horizontal position when swimming freestyle so that there is less side-to-side movement. If you generate more side-to-side movement, the drag effect increases and you have to output a lot more energy to move forward.
In freestyle, butterfly and backstroke there are two phases of the stroke- the pull-through and recovery. The pull-through involves adduction and internal rotation of the shoulder as the elbow flexes and then extends. Propulsion is achieved in the pull-through phase. The recovery phase involves abduction and external rotation of the shoulder, followed by elbow flexion and then extension.
A breakdown of the freestyle stroke according to the North American Journal of Sports Physical Therapy:
Freestyle requires a combined motion of scapular retraction and elevation, with humeral abduction and external rotation during the recovery. During the pull-through phase, the scapula is protracted while the humerus is adducted, extended, and internally rotated. Stroke power is achieved through the shoulder adductors, extenders, and internal rotators with the serratus anterior and latissumus dorsi being the key propulsion muscles for swimmers. Because the trunk is rotated away from the side that is beginning to pull, the shoulder avoids a true impingement position of forward flexion with internal rotation and horizontal adduction.
For swimmers, the shoulder goes through a wide range of motion in order to execute the strokes. Shoulders have to have good mobility to execute strokes, as well as bony support to provide protection and stability to the joint. Proper shoulder motion requires a complex set of muscles to help control and stabilize the region. The rotator cuff muscles control and protect the shoulder joint and the scapular stabilizers control and protect the shoulder blade. The rotator cuff muscles have to contract to prevent the round surface of the upper arm from sliding excessively within the shoulder joint. Additionally, the scapular stabilizers, which connect the shoulder blade to the rib cage, have to hold the shoulder blade tight against the body as well as slide and rotate the shoulder blade as the arm moves.
If the scapular stabilizing muscles are weak and the short scapulohumeral muscles tight, there will be insufficient movement of the shoulder blade during the swimming stroke and there will be a tendency for rotator cuff impingement. Rotator cuff impingement can also occur if there is less mobility in the cervical and thoracic spine.
Repetitive injuries are the most common types of injuries in swimming. They occur slowly over time as a result of performing the same motion over and over. Shoulder pain is the most common musculoskeletal complaint in swimming with reports of incidence of disabling shoulder pain in competitive swimmers ranging from 27% to 87%. A competitive swimmer usually exceeds 4000 strokes for one shoulder in a single workout, making this sport a common source of shoulder pathology. Over the time spent training, the repetitive physical stress of swimming places more demand on the shoulders.
The repetitive forces can lead to strain and irritation of the rotator cuff and scapular stabilizer musculature. As training continues, micro-traumas can develop. At first this may be hard to notice and can just feel achy or tight in the shoulder. Our bodies attempt to repair this by laying down new tissue to the damaged area. This is called scar tissue and it is important to form in order for the healing process to occur. However, over time, from the repetitive demand that swimming places on the shoulders, as the muscles continue to be repaired, scar tissue can build up and form adhesions. Adhesions will interfere with normal function of the muscles and now the shoulder is strained even further, eventually leading to more microtrauma. As this cycle continues, muscles stop functioning normally, restricting movement, which in turn causes pain and can lead to chronic issues.
What can you do?
Fortunately, you do not have to give up swimming! The adhesions must be addressed in order to restore full strength and function of the muscles. Active Release Technique (ART) and are forms of treatment that can address the problems in the muscles, ligaments, fascia and nerves. For swimmer’s shoulder, these techniques specifically locate and treat scar tissue adhesions that accumulate in the muscles and surrounding soft tissues.
ART allows the practitioner to:
1. Break-up restrictive adhesions
2. Reinstate normal tissue flexibility and movement
3. More completely restore flexibility, balance, and stability to the injured area and to the entire kinetic chain
Dry Needling allows the practitioner to:
1. Short circuit the vicious pain cycle in a direct way
2. Release adhesions, allowing muscle to return to normal length
3. Restores proper function to the abnormally behaving muscles
After the adhesions are addressed, other approaches such as stretching and exercises help with relief and recovery from swimmer’s shoulder. Swimmer’s shoulder is a condition that Grove Spine & Sports Care providers treat. The combination of ART and Dry Needling with rehabilitation exercises increase the recovery time for the swimmer and is the most effective way of treating swimmer’s shoulder. We can keep you in the water for the hot summer months!
If you have questions regarding swimmer’s shoulder or treatment options, please contact Dr. Speares at firstname.lastname@example.org or call for an appointment today 703-760-8110!
• Brukner, Peter and Karim Khan. (2007). Clinical Sports Medicine (3rd ed.). Australia: McGraw-Hil
• N Am J Sports Phys Ther. 2006 Nov; 1(4): 166–175.