Objective: Examine whether pre-intervention physical activity (PA) level is associated with achieving a positive treatment response of pain and/or function improvement after a 12-week exercise intervention in participants with knee osteoarthritis (OA).
Methods: We performed a secondary analysis of a randomized, single-blind comparative effectiveness trial showing similar treatment effects between Tai Chi mind-body exercise and standard physical therapy intervention for knee OA. Baseline PA was assessed by Community Healthy Activities Model Program for Seniors (CHAMPS) Questionnaire and, in a subsample, by tri-axial accelerometers.