Efficacy of Eccentric Exercises in Individuals with Frozen Shoulder

Frozen shoulder is a musculoskeletal condition with a strong negative impact on activities of daily living, producing pain, disability, anxiety, and sleep disorders. It has a worldwide prevalence of 5.3%, increasing from 10 to 38% in patients with diabetes and thyroid conditions. This clinical entity manifests itself mainly in women between 40 and 65 years of age. Its resolution time is long and can reach 42 months with symptoms that persist throughout life.

In the clinical evaluation, patients with Frozen Shoulder are manifested mainly by presenting mobility deficits. Previous studies described different structural alterations that may justify this clinical condition and its consequences, such as, for example, fibrosis of the coracohumeral ligament, alterations of the rotator interval, and of the axillary recess.

Although passive structures are believed to be primarily involved in this condition, A series of five cases in which patients with frozen shoulder presented a significant increase in mobility after a general anesthetic block. The data obtained from this study and the different complications presented by patients with CH suggest that it is necessary to further understand the role of the rotator cuff in this clinical condition.

Eccentric exercises consist of contracting the muscle to control or decelerate a load while the muscle or tendon is lengthening or remaining stretched. This intervention has been proposed for the treatment of tendinopathies in different body regions.

A randomized controlled clinical trial with two parallel groups will be carried out. Evaluators will be blinded to the treatment group and therapists will be unique to each group. This study will follow the CONSORT guidelines.

Randomization by blocks between groups will be carried out through the website www.randomization.com and the sequence will be stored in sealed and opaque envelopes to maintain allocation confidentiality. This process will be carried out by an independent researcher, who will not be involved in the assessment and treatment. The allocation of subjects will be revealed to the researcher responsible for the treatment by opening the envelope before the start of the intervention. The researcher responsible for the evaluation will be blinded to the treatment group. The individuals will be blinded in relation to the study hypothesis and will not have contact with the participants of the same or the other group.

Initially, all participants will undergo screening to assess the inclusion and non-inclusion criteria of the study. All individuals who meet the eligibility criteria will undergo an anamnesis to collect personal, sociodemographic, pain history, and primary and secondary outcomes measurements.

Eligibility Criteria:
Inclusion Criteria:

* History of diffuse-onset shoulder pain of at least one month
* Gradual loss of passive external rotation of at least 50% compared to the contralateral side

Exclusion Criteria:

- History of shoulder fracture/ surgery

* Shoulder pain reproduced by passive movement of the cervical spine
* History of rheumatoid arthritis
* Shoulder immobilization for more than 5 days
* Bilateral frozen shoulder