HIIT for Inflammatory-driven Shoulder Pain.

This feasibility study investigates whether high-intensity interval training (HIIT) is feasible and acceptable for individuals with long-term shoulder pain where low-grade inflammation is suspected. Many patients do not recover fully with current local treatments, and systemic factors such as inflammation, and metabolic changes, additionally disturbances in the functioning of the nervous system often seem to play a role. HIIT is a time-efficient form of exercise that has been shown to improve inflammation and metabolic values and positively influence the balance of the nervous system. In this feasibility study, the investigators are enrolling 15 individuals with persistent shoulder pain (diagnosed with rotator cuff-related shoulder pain or frozen shoulder) with \>3 months of symptoms, and 15 individuals without shoulder complaints. All participants will undergo measurements of inflammatory levels, glycosylated hemoglobin (HbA1c), blood pressure, body composition, pain sensitivity tests, and complete questionnaires about autonomic complaints and quality of life. Participants with shoulder pain will also perform one personalized HIIT session on a cycle ergometer. The investigators will assess whether participants accept a systemic intervention for their shoulder pain, if they are cooperative, and how they feel about the session; additionally, any side effects will be recorded. The aim is to determine whether HIIT is practically feasible and safe for this group and whether there are indications that systemic factors such as inflammation and nervous system function are associated with persistent shoulder pain. The outcome will determine whether follow-up research with a larger study is worthwhile.