An Innovative Therapeutic Exercise Approach Based on Load Progression Criteria for the Management of Shoulder Impingement Syndrome: a Randomized Controlled Trial

Shoulder pain is a common condition affecting our society. It is estimated that between 7 and 67% of the adult population will suffer from shoulder pain at least once in their lifetime. Some research suggest that shoulder impingement syndrome (SIS) is responsible for 44 to 60% from the medical consultations regarding shoulder pain with an approximate prevalence of 70-200 per 1000 adults, which implies a remarkable use of health care resources.

Among all the musculoskeletal injuries affecting the shoulder complex, SIS remains as the most common condition, characterized for leading to loss function and disability. Its pathogenesis is associated with the affection of diverse structures and tissues like the subacromial bursa, rotator cuff tendons, acromion, coracoacromial ligament and the long head of biceps brachii. The etiology of this condition comprises multiple causes, including capsular tightness, alteration of shoulder kinematics with scapula dysfunction and muscle imbalance, and also the overuse factor.

Treatment modalities to deal with SIS embrace both surgical procedures, i.e., arthroscopic subacromial decompression) and conservative approaches (i.e., physical therapy), becoming the therapeutic exercise increasingly popular due to arising evidence from the last 30 years. Furthermore, with regard to potential effects, therapeutic exercise presents itself as a safer and less aggressive alternative, causing fewer adverse effects than pharmacological or surgical options, which are relegated preferably as secondary choices.

There is a wide evidence supporting the exercise therapy as an effective strategy for the management of SIS. However, some controversy exists regarding the optimal approach in terms of intensity, frequency and number of repetitions. Thus, a program acting as a gold standard for the development and progression of the proposed exercises is still lacking, especially when attempting to estimate the pure effect of progressive exercise in isolation between experimental and control group.

Prior research evaluating the effect of progressive exercise for the management of SIS usually included programs with a duration of 3 months. However, other studies established follow-up periods of either one month and a half or, conversely, more than 6 months. That, together with the wide variety of post-treatment follow-ups, makes it difficult to find the optimal period where the results derived inherently from the intervention and not from the natural course of the condition may be observed.