This study investigates how well individuals with knee osteoarthritis can learn to alter their calf muscle activation using haptic biofeedback while walking and evaluates how these changes affect knee loading. Prior research has utilized musculoskeletal simulations to determine that reducing the activation of one of the calf muscles, the gastrocnemius, can have a large impact on reducing knee loading. However, this has not been tested in individuals with knee osteoarthritis. In this study, participants will be trained to alter the activation of their gastrocnemius muscle, by receiving haptic feedback after each step. The feedback will indicate how the participant changed their muscle activation relative to baseline. Some participants will train on a treadmill in the laboratory for up to two sessions, with 30 minutes of walking with feedback in each session. If a participant can learn to adjust their muscle activation in the first training session, they will be able to complete the second training session. Other participants will train outside the laboratory for one session with 30 minutes of walking with feedback to investigate changes in knee loading while using the new walking strategy during over-ground walking. The movement data collected during the training sessions will be used as inputs to computer simulations of the musculoskeletal system to determine if walking with the new muscle activation strategy reduces knee loading.