Footwear and Exercise for Knee Osteoarthritis (FiREwORK Trial)

Off-the-shelf commercially available shoes will be used compliant with previously published criteria: (i) heel height \<15 mm, (ii) shoe pitch \<10 mm, (iii) absent arch support/motion control, (iv) minimal sole rigidity, (v) weight \<=200g (+/-10%). Participants will be instructed to wear the shoes at least 4 hours daily for the duration of the 9-month intervention and to avoid wearing other types of shoes, if possible.

Off-the-shelf commercially available shoes will be used compliant with previously published criteria: (i) heel height \>30 mm, (ii) shoe pitch \>10 mm, (iii) present arch support/motion control, (iv) sole rigidity, (v) weight \>300g (+/-10%). Participants will be instructed to wear the shoes at least 4 hours daily for the duration of the 9-month intervention and to avoid wearing other types of shoes, if possible.

The 3-month supervised exercise program will consist of one group session per week of approximately 30 minutes complemented with home-based exercises 3 times per week. Group sessions will consist of a 10-min warm-up followed by a circuit training of strengthening and/or neuromuscular exercises. Subsequently, during a 6-month unsupervised home exercise program, participants will perform strengthening exercises of the lower limb muscles 3 times weekly. Throughout the 9-month intervention, participants will be encouraged to maintain a daily routine of aerobic exercises, consisting of structured activity bouts of at least 10 minutes at a moderate intensity (grade 5-6 (out of 10, maximum exertion) on a Rate of Perceived Exertion scale), achieving at least 70 minutes of weekly physical activity at 3 months and 150 minutes at 9 months.