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Background and Etiology

A tendon is part of the muscle that attaches muscle to bone. It is a strong, fibrous tissue that is responsible for transferring the forces generated by the muscle to the bone, thus producing movement at the joint. When a tendon becomes irritated or inflamed it becomes painful, especially with movement. Inflammation of the tendon is called tendinitis.

Tendinitis of the shoulder is common due to the anatomy of the shoulder and the amount of activity and stress placed on this joint. Most tendinitis at the shoulder occurs in the subacromial space. The subacromial space is an area on the top the shoulder that is formed by the arch created by the acromio-clavicular joint, coraco-acromial ligament and acromion (outer edge of the scapula, or shoulder blade). This is called the coracoacromial arch.

The primary tendons of the shoulder, including the rotator cuff tendons and long head of the biceps tendon pass under this arch. Anything that compromises this space places these tendons at high risk for friction, rubbing and irritation, which sets the stage for a case of tendinitis. Tendon problems are most common between 40-60 years of age, but also occur in the younger population with overuse sport injuries.

Tendinitis is most often an overuse repetitive strain injury (RSI). Tendons that have an area of poor blood supply are most susceptible to inflammation and development of tendinitis (for example, the supraspinatus). Other high risk activities or conditions that can lead to the development of shoulder tendinitis include:

  • Participating in activities that require overhead motion like swimming, tennis, softball, baseball, or overhead throwing activities, which may aggravate the shoulder.
  • Repetitive strain injuries (RSI) at work or through overuse activities are common in people who participate in sport activities or have jobs that require performing activities of a repetitive nature, like working an assembly line
  • Sudden trauma or an accident like a fall on the shoulder
  • Patients with rheumatoid arthritis may be susceptible to tendinitis
  • Age related changes in the tendon elasticity and circulation make the tendon more susceptible to injury and reduce its ability to heal
  • Postural factors like a forward head and shoulder posture that reduce the subacromial space can lead to irritation of the shoulder tendons
  • Overload injuries like lifting heavy objects or weight training can strain and irritate a tendon.
  • Weakness of the rotator cuff can cause a muscular imbalance that results in shoulder impingement (pinching) of the tendons due to poor mechanics in the subacromial space. This can eventually produced a tendinitis.
  • Shoulder pain or tenderness directly over the tendon that can radiate to the upper arm
  • Pain or burning sensation during active motions and resisted movements or activities
  • Pain with overhead activities or sleeping on the effected side
  • Difficulty dressing and performing activities of daily living
  • Weakness may occur as the inflammation gets worse
  • Feeling of tightness or loss of motion due to discomfort
  • Swelling of the tendon

The most commonly involved muscles and tendons in the shoulder are:

  • Supraspinatus – one of the rotator cuff muscles and often involved in impingement problems. This tissue is notorious for poor blood supply at the tendon level. Commonly causes problems in overhead athletes and those who use repeated throwing motions.
  • Infraspinatus and Teres Minor – are rotator cuff muscles whose function is to turn the arm away from the body (external rotation)
  • Subscapularis – a rotator cuff muscle whose primary function is to turn the arm toward the body
  • Long head of the Biceps – is responsible for bending the elbow (flexion), turning the forearm (supination) and assists in raising the arm over head. It is commonly irritated with repetitive overhead activities and routine lifting and chores. The tendon can weaken with age and rupture.

If one suspects they have tendinitis, the initial treatment should consist of avoiding the positions and activities that produce the pain. A course of conservative treatment is usually recommended that would include rest, ice, physical therapy and nonsteroidal medications to reduce inflammation. If symptoms persist, treatment by your physician may be necessary. This may include steroidal medication or injections, in conjunction with therapy. In severe cases surgical intervention may be needed to correct any mechanical causes of the tendon irritation.

Physical Therapists are professionals, educated and trained to administer interventions. As stated in The Guide to Physical Therapist Practice, interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis, and goal of the patient or client. Common interventions in the treatment of Shoulder Tendinitis include:

  • Manual Therapeutic Technique (MTT): hands on care including soft tissue massage, deep friction massage and joint mobilization by a physical therapist to regain mobility and range of motion of the shoulder and tendon.
  • Therapeutic Exercises (TE) including stretching and strengthening exercises to regain range of motion and strengthen the shoulder and effected muscle.
  • Neuromuscular Reeducation (NMR) to restore stability, retrain the upper extremity, and improve movement technique and mechanics (for example, throwing, lifting and over head activities) in daily use of the involved upper extremity.
  • Modalities that can include the use of ultrasound, electrical stimulation, ice, cold laser and others to decrease pain and inflammation at the shoulder and tendon.
  • Home program that includes strengthening, stretching and stabilization exercises as well as instructions to help the person perform daily tasks and advance to the next functional level.

Procedures that your physician may recommend and perform in addition to physical therapy.

  • REST and ICE
  • The use of NSAIDS (Non Steroidal Anti-Inflammatory Drugs)
  • Steroidal injections to reduce inflammation
  • Pain medication to reduce the discomfort and allow the patient to perform the recommended exercises
  • Surgery to correct underlying pathology or the cause of the tendinitis in the case of a significant impingement or instability that can produce shoulder tendinitis.


Most people recover full function following a course of conservative care that includes physical therapy, medication and/or injections. Those with more involved situations such as impingement with bone spurs will do well with surgical decompression of the area. Tendon tear outcomes depend on the size of the tear, integrity of the tissue, age and preoperative condition of the patient. Please refer to the Rotator Cuff Tear section for more information on tendon tears.


It is easier to prevent tendinitis than to treat it. Below are some tips to reduce the risk of tendinitis.

  • Warm up lightly before activity to improve circulation and lubricate the muscle and tendon. Warm up should be performed to the area that will be used.
  • Stretch the tendons and muscles you will be using after your warm up prior to the activity, and after it. Do not bounce when stretching. Instead, hold the stretch for 15-20 seconds.
  • Strengthen the muscles and tendons that you need to use for your activity. A regular strengthening program three times a week will keep muscles prepared for the job you are asking them to perform.
  • Do not work through pain. Listen to your body. Avoid the “no pain, no gain” philosophy.

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