SEX DIFFERENCES IN KNEE OSTEOARTHRITIS PROCESSES: THE ROLE OF MUSCLE STRENGTH IN EXPLAINING ACUTE PAIN INTENSITY, PAIN SENSITIZATION, KNEE JOINT MOMENT AND MUSCLE ACTIVATION RESPONSES TO A STANDARD CONTINUOUS WALK

Abstract

Walking is prescribed for knee osteoarthritis management but evidence to support specific walking prescriptions is lacking. Given that osteoarthritis manifests itself differently between sexes, are sex-specific walking prescriptions needed? This study determined differences between sexes in pain, moment and muscle activation responses to a 30-minute walk in individuals with radiographic knee osteoarthritis, and whether muscle strength explained variability in responses. Forty-five (23 females) participants with radiographic medial knee osteoarthritis were included. Independent t-tests determined males had higher strength, knee flexion moment-knee extension moment difference, and lower pain sensitization and muscle activity than females (p<0.05). Two-way mixed ANOVAs found significant sex by time interactions (p<0.1) where males, but not females, increased their pain sensitization and knee adduction moment (KAM) features post-walk. Linear regression models indicated strength explained 11% of the variance in KAM 1st peak response. Different magnitudes and directions in responses between sexes support the need for sex-specific walking prescriptions.