Altered muscle synergies in knee osteoarthritis patients during locomotion tasks persist over six-week valgus brace intervention

Persistently increased hip flexion moments in the KOA group, possibly caused by increased sagittal trunk flexion, appeared to drive elevated activity of the biarticular knee flexor synergy. Increased knee flexor synergy activity can result in elevated knee joint contact forces, potentially aggravating KOA progression. Rather than being caused solely by the need for local stability, increased knee flexor synergy activity may be driven by altered trunk dynamics, which remained unaffected throughout the brace intervention.