What Causes Swimmer's Shoulder? An Overview of the Injury

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Swim coaches frequently encounter swimmers complaining of shoulder pain in one or both of their shoulders. This pain (and its underlying cause) is often associated with swimming freestyle, and seems to occur most often in the swimmer's anterior shoulder region, but could also occur in other shoulder regions. When reported by swimmers, this pain or injury is often termed swimmer's shoulder (SS). SS and can limit or stop training and hinder performance. If it were possible to employ specific methods and techniques to limit the impact of SS on a swimming program and its athletes, it would be a valuable addition to the overall training plan of that program and its individual swimmers. Maximizing the athlete's availability to train (and to compete) is important to advancement in sports achievement.

Identifying and employing methods to decrease the incidence, duration, or intensity of SS episodes could allow an affected athlete to return to training or competition sooner, or could prevent an athlete from encountering an SS injury. Reducing the occurrence of SS or reducing the time needed to rehabilitate the athlete from that injury if it occurs, could lead to valuable reductions in lost training time for swimmers. Employing several preventative and rehabilitative methods can reduce losses in a swimmer's training availability from shoulder pain or shoulder tissue damage commonly known as SS. These methods to control SS include technique modifications, appropriate considerations in program and training design, appropriate flexibility development and maintenance, and strengthening exercises.

Freestyle or front crawl involves an overhead arm motion repeated many times in a single workout. It is the most often used technique in a swimming workout. Swimmer's shoulder (SS) is a general term for pain in the shoulder area of a swimmer that could be encountered when performing freestyle. In this paper, SS will be limited to an impingement in the subacromial area or other similar dysfunctions in closely related shoulder regions. Overuse is defined as employing a movement of a structure more frequently than that which the structure is prepared. Overtraining is related to this, as it is doing more overall work or work at a higher intensity level than that which the swimmer is prepared; overtraining could result in overuse. The primary causes of shoulder problems in a swimmer are those related to SS. Athletes with this specific shoulder injury can be treated and rehabilitated by utilizing simple methods. The occurrence of SS injuries can be decreased through the utilization of certain methods and techniques.

Swimmers can make changes to their routines that allow them to incorporate these methods to decrease the frequency of SS incidences. Many things could lead to shoulder injuries in a swimmer that are not related specifically to their swimming, or specifically to performing freestyle. Damage from a shoulder injury could be so severe that basic rehabilitative or preventative measures will not be effective. Some athletes will not want to rehabilitate their injury with the intention of returning to swimming and instead may choose to stop participation. It is generally accepted that an athlete needs to train to improve. If an athlete is injured, and that injury is so severe or painful as to require training activity be limited or stopped, it is unlikely that the athlete will be able to improve as much as if they were not injured. If the injury stops that athlete's participation in the sport, the situation is even worse. Decreasing or preventing injury occurrences is, therefore, an important consideration when dealing with athletes.

Swimmers frequently report that they have shoulder pain, often indicating a case of SS. If the causes of this pain can be addressed, to limit or eliminate the effects of the injury causing the pain, there should be a greater chance for swimmers to train, improve, and compete in their chosen sport.

Swimmers Shoulder is frequently described as an impingement problem in the rotator cuff area, felt as anterior shoulder pain

Anderson, Hall, and Martin describe the initial symptoms as the pain felt deep in the shoulder, often at night, and that increases with activity in the impingement position. The pain may only be felt in a painful arc between the waist and shoulder. This painful arc is described by Anderson, Hall, and Martin as being between 70º and 120º during active or resisted abduction of the shoulder. A study by Bak and Fauno reported swimmers described the pain as localized in the anterior or anterior-lateral shoulder area. The pain may gradually increase over time, indicating an impingement, as opposed to a sudden onset of pain, which would indicate a tear.

Both the Hawkins and Neer test could be positive, with the Hawkins test indicating a compression of tendons under the acromion, and the Neer indicating a rotator cuff pinching on the anterosuperior glenoid rim. In a case review by Koehler and Thorson, the following signs were noted in a swimmer with no previous history of shoulder problems that was now complaining of shoulder pain:

  • Shoulder pain while swimming freestyle.
  • A forward shoulder slouch while seated.
  • Underdeveloped posterior shoulder musculature.
  • A mild winging on the affected side's left scapula.
  • Tenderness in the acromioclavicular joint and coracoid process in the impingement area.
  • Tenderness in the affected side's bicep tendon and supraspinatus tendon.
  • A full range of motion in all planes.
  • Strength was slightly decreased in the supraspinatus and infraspinatus.
  • Full strength in the internal rotators, arm extensors, and flexors.
  • Moderate posterior and anterior laxity in both shoulders.
  • A bilateral sulcus sign.
  • Impingement and adduction-compression tests on the affected side were positive.
  • An apprehension test on the affected side was negative.

They concluded that the swimmer had an impingement syndrome consistent with SS that included weakness in the rotator cuff and scapular stabilizers and multidirectional instability. Bak and Fauno state that the majority of swimmers with shoulder pain have signs of impingement, increased shoulder laxity anteroinferiorly, and a lack of scapulohumeral coordination, supporting Koehler and Thorson (1996). The pain from SS can be divided into four increasingly more severe categories:

  1. Pain only present after heavy workouts.
  2. Pain present during and after workouts.
  3. Pain present that interferes with performance.
  4. Pain that prevents participation.

If possible, at the first sign of any SS symptom, an evaluation for other symptoms should be undertaken before the condition escalates. It may also be possible to isolate the cause or causes of this occurrence of SS and develop an appropriate rehabilitation or prevention plan.

There are many possible reasons for SS to develop. SS injury and pain from impingement and other related issues seems to occur under one or more of the following circumstances. SS is considered an impingement related injury that seems to develop through a mechanism related to overuse or instability. 

  • faulty stroke mechanics
  • sudden increases in training loads or intensity
  • repetitive micro traumas related to overuse
  • training errors (such as unbalanced strength development)
  • use of training devices like hand paddles
  • higher levels of swimming experience
  • high percentage of freestyle swum in practices
  • weaknesses in the upper trapezius and serratus anterior
  • weakness or tightness of the posterior cuff muscles (infraspinatus and teres minor) or a hyper mobile or very lax shoulder joint.

Swimmers perform a great number of overhead arm motions in the course of a normal practice week; Pink and Jobe estimate that some swimmers may complete as many as 16,000 shoulder revolutions in a one week period, while Johnson, Gauvin, and Fredericson estimate this number could be as high as 1 million per year. To gain a sense of scale, Pink and Jobe compare swimmer's arm motions with 1,000 weekly shoulder revolutions for a professional tennis player or a baseball pitcher.

Given the swimmer's quantity of movements and the range of those movements, micro traumas are inevitable, and damage from repeated micro traumas can develop into SS. It appears that there are three main syndromes behind SS:

  • instability
  • impingement
  • tendonitis

Tuffey lists the triad of problems involved with SS as:

  • biceps tendonitis
  • subacromial bursitis
  • rotator cuff tendonitis usually in the supraspinatus muscle.

Richardson, Jobe, and Collins summarize SS as a chronic irritation involving the humeral head and rotator cuff interacting with the coracoacromial arch during shoulder abduction resulting in an impingement, as do Otis and Goldingay.

Anderson, Hall, and Martin (2000) list a systematic process of rehabilitation and management for an impingement like SS (listed below), which also includes elements listed in other works. These steps can be used to rehabilitate from SS:

  • Initially, use cryotherapy
  • Later change to contrasting treatments of moist heat and cryotherapy twice per day
  • Pain management may be facilitated through electronic stimulation (Chang, 2002; Costill, Maglischo, & Richardson, 1992; Pollard & Croker, 1999).
  • Ultrasound treatments and nonsteroidal anti-inflammatory medication can be used to reduce inflammation 
  • Attempt to eliminate movements that cause pain for 4-6 weeks and avoid abduction above 90º
  • Correct technique flaws that produce shoulder stress 
  • Stop using hand paddles, stop partner-assisted stretching, and stop overhead training 
  • Use wand, T-bar, or other stretching exercises to improve mobility (but not hypermobility)
  • Employ pain-free isometric and elastic cord exercises with low resistance and a high number of repetitions two to three times daily to maintain muscle tone
  • Control humeral head superior displacement by strengthening the infraspinatus and teres minor 
  • Add high-speed isokinetic exercises and diagonal pattern elastic band exercises after 4-6 weeks
  • Allow a gradual return to full activity if symptoms are absent and do not reoccur


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