Walking While Acting Sad and Happy Emotions Influences Risk Factors of Knee Osteoarthritis.

Greater knee adduction moment is associated with increased risk and progression of knee osteoarthritis, and this biomechanical risk factor is modulated through kinematic gait modifications. Emotions are known to influence walking kinematics and speed, but the effect of different emotions on knee mechanics is unclear. To test this, 20 healthy participants walked while instrumented gait data was recorded. Participants initially walked naturally (baseline) and then acting 4 emotional walking conditions: Anger, Happy, Fear, and Sad, in randomized order. Statistical parametric mapping with an analysis of variance model determined the extent to which emotions influenced knee joint mechanics. Results indicated both the happy (P = .009) and sad (P < .001) condition resulted in lower knee adduction moment compared with baseline. Walking both happy and sad also resulted in walking speed changes from baseline (P < .001). A secondary analysis of covariance model with speed as the covariate indicated no significant effect of emotional condition on knee adduction moment (P > .05), which suggests that the changes from baseline can be attributed to the changes in walking speed. Decreased knee adduction is associated with reduced osteoarthritis progression and increased knee function, suggesting that walking while acting different emotions, specifically happy and sad, may moderate knee osteoarthritis risk.