Introduction: Shoulder disorders cause significant impaired function and health-related quality of life. Treatment consists of either conservative or surgical treatment, and results in substantial health care utilization. Strengthening exercises of the rotator cuff muscles are often included in physiotherapy treatment of patients with shoulder disorders. Valid and reliable measurement methods to assess shoulder muscle strength are important to analyse the efficacy of treatment in both clinical practice and research. There is a need for an up to date systematic review that summarize the evidence of measurement properties of objective measurements of isometric and isokinetic shoulder muscle strength in individuals with and without shoulder symptoms. Aim: The aim of this review is to investigate measurement properties of objective methods to assess shoulder muscle strength. Methods: The following databases; Cochrane Central Register of Controlled Trials (CENTRAL), Pubmed, EMBASE, and PEDro will be searched for relevant studies reporting the assessment of measurement properties of objective methods used to assess shoulder muscle strength. The methodological quality will be assessed with the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. The overall evidence of the measurement properties of the included instruments will be summarized in a best evidence synthesis.
- Measurement properties