Physical activity on prescription in patients with hip or knee osteoarthritis: A randomized controlled trial.

The two interventions were quite similar, as both included individualized advice and behavior change techniques, making it difficult to isolate the effect of the prescription and follow-ups. There was no true control or placebo group, so improvements in both groups cannot be definitively attributed to the interventions rather than natural history or regression to the mean. The study sample was relatively physically active at baseline, leaving little room for major improvements. Dropout rates for accelerometer data were 20%, which could have led to a type-2 error (missing a true effect). The significant finding for pain after walking was a secondary outcome and may be due to multiple testing or baseline differences.

The authors declared no conflicts of interest. Funding was provided by the Uppsala-Örebro Regional Research Council and the Centre for Research and Development Uppsala University/Region Gävleborg, which had no influence on the research or data interpretation.

Do not conclude that physical activity prescriptions are ineffective. The study compared two active interventions, both involving individualized advice. The null result means the *additional* components (written prescription, follow-ups) did not add benefit over the *core* component (one hour of tailored advice). It does not show that advice alone is insufficient, but rather that the more intensive version was not superior.