Pre-Exercise And Acute Movement-Evoked Pain Trajectories During A 24-Week Outdoor Walking Program For Knee Osteoarthritis (Walk)

Objectives Exploring (1) pre-exercise and acute movement-evoked pain (AMEP) during an outdoor walking program in individuals with knee osteoarthritis (OA); and (2) comparing baseline physical performance and AMEP flares initiated by walking between participants with either a higher or lower attendance rate. Methods Individuals with knee OA were prescribed a 24-week walking program, including one unsupervised walk and two supervised walk classes per week. Participants self-reported knee pain on a numerical rating scale (NRS;0-10) before and after each supervised class. Mixed-effects models were used to investigate trajectories over time for pre-exercise pain and AMEP change (post- minus pre-exercise pain; positive value indicates flare-up). Baseline physical performance (6 tests) and AMEP flares were compared between participants with higher (attending ≥70% of supervised classes) and lower attendance rates. Results Of 24 participants commencing the program, 7 (29%) withdrew. Over 24 weeks, pre-exercise pain improved by 1.20 NRS (95% CI -1.41 to -0.99), with estimated largest per class improvements during the first 8 weeks (-0.05 (-0.06 to -0.03) and plateauing around 20-weeks. The AMEP was estimated to improve by 0.19 NRS (95% CI -0.38 to -0.004) over 24-weeks, with improvements plateauing around 12-weeks. Participants with lower attendance (n=11) scored poorer on all physical performance tests and experienced a slight increase in AMEP during the first two weeks of the program. Conclusions Participants improved in pre-exercise pain and AMEP in the first 20 and 12 weeks, respectively. Despite supervision, physical performance and AMEP flares may have contributed to lower attendance. Trial registration number 12618001097235