Association Between Changes in Shoulder Strength and Self-Reported Shoulder Symptoms in Patients With Hypermobility Following 16-Weeks of High-Load or Low-Load Exercise: A Secondary Analysis of an RCT.

The analysis is observational in nature even though the treatment was randomised: it shows that strength gains and symptom improvements occurred together, not that gaining strength caused the improvement. The authors state plainly that this prevents them from making recommendations for clinical practice. Only 76 of the 100 people recruited had complete strength and symptom data at both time points and were analysed. The 24 left out were not counted in the results. It was an exploratory analysis of data from an already-finished trial, with no sample size calculation and no correction for testing many comparisons at once, so some of the significant findings could be chance. The statistical models explained little of what happened: the reported correlations were below 0.3, meaning strength changes account for only a small part of the change in function or pain, and the estimates may have been influenced by outliers. Psychological and social factors known to affect shoulder prognosis, such as pain experience, fear of movement and catastrophising, were not measured or adjusted for. Everyone had shoulder symptoms for at least 3 months, was aged 18 to 65 and came from primary care in one region of Denmark, and most were women. Results may not carry over to other groups. Only the most severely affected shoulder of each person was analysed, which limits the sample size and may affect people whose shoulders are equally affected.

The trial was funded by the Region of Southern Denmark, Esbjerg municipality, the Danish Rheumatism Association, the Fund for Research, Quality and Education in Physiotherapy Practice and the University of Southern Denmark. These are public, professional and charitable funders, not a company selling the exercise programme or any product used in it. One co-author reports personal fees from the Journal of Orthopaedic and Sports Physical Therapy, grants from the Lundbeck Foundation and personal fees from Munksgaard, and is a co-founder of GLA:D, a non-profit initiative for implementing osteoarthritis guidelines. Another co-author reports grants from AstraZeneca, both outside the submitted work.

Do not read this as evidence that strengthening the shoulder is what makes these patients better. It is a secondary, exploratory look at associations in 76 people, the models explained only a small part of the change in function and pain, and the many comparisons were not adjusted for, so the associations reported here cannot be turned into a treatment target or a promise to patients.