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.~Regarding the progression criteria, there seems to be a tendency to consider the modulation of the painful sensation as the main benchmark from which the exercise may progress in difficulty, but some other progression sub-criteria can also be found, such as fatigue or subjective perception. Furthermore, the presence of other conditioning elements, like proximity to pain threshold or a certain reference value in the Visual Analogue Scale (VAS), reduces the homogeneity among the exercise programs and hinders the standardization of the ideal exercise progression when performing the exercises for the management of SIS.~The main objective of this clinical trial is to prove the efficacy of a progressive exercise program based on strength and resistance training in comparison to an exercise protocol from the literature to increase neuromuscular and cardiorespiratory capacities and improve the symptoms in subjects with SIS. In addition, we propose to determine the existence or not of statistically significant differences between treatment modalities by evaluating whether these changes occur before, during or after the application of the proposed exercise protocol.
Upper limb tendinopathies, especially the so called shoulder impingement syndrome, is a common injury among the population. Its management usually involves active treatments, being the therapeutic progressive exercise the most important and effective modality. However, whether a certain criterion is more appropriate than another when progressing the exercise program remains unclear. We propose a new program based on progressive exercises serving as a standard approach for the management of shoulder impingement syndrome.