Rotator cuff tendinopathy, also called subbracromial impingement syndrome, is one of the most important causes of anterior shoulder pain. The most frequently affected structure in rotator cuff tendinopathies is the supraspinatus tendon due to its position in the subacromial space. Histological examinations of rotator cuff tendinopathy revealed that the structural changes in supraspinatus tendon injuries are similar to those of the patella and Achilles tendon injuries.

In the treatment of Achilles and patellar tendinopathy, it has been shown that eccentric exercise training has positive effects on pain and function, and supports the improvement in the structural and mechanical properties of the tendon. This success of eccentric training in managing lower extremity tendinopathies has encouraged researchers to conduct more scientific studies to develop evidence-based eccentric training guidelines for the conservative treatment of tendinopathies in the shoulder region. Studies showing that eccentric exercise training has positive effects on pain and function in rotator cuff pathologies have begun to take their place in the literature. In some studies, it has been stated that eccentric exercises are a safe and tolerable approach even in patients with rotator cuff tendinopathy who are candidates for arthroscopic subacromial decompression surgery and reduce the number of patients who are candidates for surgery. Again, in a systematic review-meta-analysis study involving individuals with rotator cuff tendinopathy, it was once again summarized that eccentric training has positive effects on pain and function, but it was stated that more studies are needed on this subject.

The HSR training is the repetitive gradual and slow contraction of the muscle against the heaviest possible load that the person can tolerate. In this training, the focus is more on the concentric and eccentric phases of the movement, and these phases are requested to be completed slowly in 3 seconds. As a result, the concentric/eccentric phase of an exercise repetition is performed with maximum weight in 6 seconds in total. There is scientific evidence in the current literature that slow resistance training has positive effects on symptoms and tendon structure in patella and Achilles tendinopathy. Beyer et al. compared eccentric exercise training and HSR training in Achilles tendinopathy and reported that both trainings had equally positive effects. However, scientific studies investigating the effects of slow resistance training in rotator cuff pathologies are mostly new and few in number. In a recent single-blind randomized controlled feasibility study conducted on 22 individuals with rotator cuff-related subacromial shoulder pain, the effects of slow resistance training in addition to traditional physical therapy program and traditional physical therapy program were compared. Schydlowsky et al. In their study comparing the effects of a supervised and home-based physiotherapy program in subacromial impingement syndrome, they did not directly examine the effects of slow resistance training, but used the slow resistance training procedure for the rotator cuff muscles.

Although exercise training is known as an effective intervention method in the treatment of rotator cuff/subacromial impingement problems, there is no definite consensus on which type of exercise is more effective. However, when previous literature studies from 2022 were examined, a single pilot study was found that examined the effect of specific slow resistance training on symptoms in rotator cuff tendinopathy; No studies could be found comparing specific slow slow resistance training with other exercise interventions. The aim of this thesis, which the investigators planned in the light of this information, is to analyze and compare the effects of heavy slow resistance training and eccentric exercise training on pain, function, supraspinatus tendon structure, muscle strength, range of motion, subjective perception of improvement and treatment satisfaction in individuals with subacromial shoulder pain associated with rotator cuff tendinopathy.