The influence of education on pain during and following acute exercise in people with knee osteoarthritis: A randomised controlled trial

Background: Explicit education about exercise-induced hypoalgesia (EIH) reduces experimental pain after a single exercise session in pain-free individuals. However, the effect in people with chronic pain is unclear. This study aimed to determine the effect of EIH education on pain during and following exercise in people with knee osteoarthritis (OA). Methods: All procedures were administered online. Participants were randomised to receive 15-min of explicit EIH education or 15-min of general education about knee OA. Participants then completed a questionnaire on their beliefs about exercise and pain, followed by a bout of home-based lower limb resistance exercise. Pain intensity (0-10) was assessed before, during and immediately after exercise. Results: 40 participants completed the study (67.3 +/- 10.8 years old, 73 % female). Participants only somewhat agreed pain could be reduced following a single session of exercise and that the education changed what they thought about exercise and pain, but these beliefs were not significantly different between groups (p = 0.053 and p = 0.104, respectively). Pain was similar between groups (adjusted mean difference [95 % CI]) during exercise (0.51 [-0.72 to 1.74], p = 0.410) and following exercise (-0.75 [-1.62 to 1.11], p = 0.087. Compared to baseline, pain (mean difference [95 % CI]) was lower during exercise (-1.01 [-1.66 to -0.36], p = 0.003) and following exercise (-0.96 [-1.5 to -0.42], p < 0.001). Conclusion: A single exercise session reduces pain in people with knee OA, but this was not influenced by preexercise education about EIH. Further research is needed to understand if and how EIH can be modulated in people with knee OA.