Effects of Training Modalities and Additional Pain Education on Exercise-Induced Hypoalgesia in People With Osteoarthritis of the Knee: A Randomised Controlled Feasibility Trial.

BACKGROUND

This randomised controlled feasibility study aimed to evaluate the feasibility of a main study and provide a first assessment of whether the exercise-induced hypoalgesia (EIH) response differs depending on the training modalities in people with knee osteoarthritis (OA) and whether it can be enhanced by education about pain.

METHODS

People with knee OA (n = 36, 60 ± 11 years, WOMAC total 51.7 ± 36.6) were randomly assigned to receive lower body resistance training (RTL), upper body resistance training (RTU), or aerobic training (AET). Each participant performed three training sessions (t1, t2, t3) separated by 1 week, and education about pain and EIH after t2. Pressure pain threshold (PPT) was measured at six sites before (PPT0), immediately after (PPT1), and 30 min after (PPT30) each training session. Feasibility was assessed using indicators for practicability, acceptance, and safety.

RESULTS

This study's procedures were deemed feasible, including high acceptance of the measurement method and educational information, well-tolerated training exercises, and a dropout rate of 8%. In each group and after each session, an EIH response could be detected at PPT1 and PPT30 (Cohen's d ≥ 0.5 to ≥ 0.8). At most measurement sites, effect sizes tended to be largest after RTL and at t3.

CONCLUSION

Progression to a larger study is warranted. RTL, but also AET and RTU may induce EIH in people with knee OA. Pain education might have a useful supporting function, but its effect would need to be determined in a study design using a control group that receives training and no education.

SIGNIFICANCE STATEMENT: Lower body resistance training, but also aerobic training and upper body resistance training may induce hypoalgesia in people with knee osteoarthritis. Being less pain sensitive after performing various exercise training modalities provides a significant benefit and can improve the quality of life of people with knee OA. If confirmed in a larger study, these findings might also allow better consideration of patients' individual preferences and potential comorbidities for exercise prescription.

TRIAL REGISTRATION: German Clinical Trials Register: DRKS00024480.