Effects of a Cycling‐Based Aerobic Exercise Program Versus a Resistance and Neuromuscular Exercise Program on Exercise‐Induced Hypoalgesia in Knee Osteoarthritis: A Study Protocol for a Randomized Clinical Trial

BACKGROUND AND PURPOSE: Exercise therapy is a core treatment for knee osteoarthritis (KOA), but the effects of different exercise modalities on endogenous pain modulation remain unclear. This trial will compare a cycling-based aerobic exercise program with a resistance and neuromuscular exercise program on exercise-induced hypoalgesia (EIH) in people with KOA and altered baseline EIH. METHODS: This randomized, two-arm, controlled, single-blind trial will include 90 participants aged 40-75 years with symptomatic KOA, knee pain intensity of at least 3 points on the Numerical Pain Rating Scale, and altered baseline EIH. Participants will be randomized 1:1 to the Cycling-Based Aerobic Exercise Group (CAEG) or the Resistance and Neuromuscular Exercise Group (RNEG). Both groups will receive 30 supervised sessions over 10 weeks. The primary treatment effect will be the adjusted mean between-group difference in within-session change in pressure pain threshold at the most symptomatic knee, averaged across weeks 1, 4, 7, and 10. Secondary outcomes include EIH at other sites, conditioned pain modulation, pain, self-efficacy, function, performance, strength, global perceived effect, adherence, and enjoyment. RESULTS: This trial will evaluate whether the two exercise programs differ in their capacity to elicit EIH in KOA. DISCUSSION: This trial may clarify whether different exercise modalities produce distinct effects on acute endogenous pain modulation in KOA and may support a more precise exercise prescription for pain management. TRIAL REGISTRATION: ClinicalTrials.gov, identifier NTC07302204.