This project is designed to identify the biomechanical mechanisms of Tai Chi (TC) exercise and test a novel optimized TC intervention by modifying newly identified mechanisms for those with knee osteoarthritis (OA) and to assess the changes in mechanical load with the intervention. It combines unique real time torque biofeedback approach, and uses external knee adduction moment (EKAM) as modulation target tailored to TC intervention in this population. The potential benefit from this project is to provide biomechanical insights of TC and this novel TC approach may produce meaningful changes of mechanical load in these patients who can learn and practice safely during this intervention.

Disabilities that arise from typical impairments of knee osteoarthritis (OA) include decreased muscle strength, reduced range of motion, and decreased aerobic cardiovascular function. A large number of individuals with knee OA experience disability and require rehabilitation. Traditional TC intervention has been a promising therapeutic intervention in knee OA, but the efficacy of TC as a knee OA intervention has proven inconclusive presumably because individuals with knee OA perform different TC components (steps) with widely varying mechanical knee joint loads. This variation could be a confounding factor in the way in which TC affects knee OA. Therefore, a feasibility study is proposed here to quantify external knee adduction moment (EKAM) response to the different TC steps, and then determine if it is feasible to use biofeedback of torque acting on the knee to modify some TC steps so as to reduce the EKAM they produce. Those TC steps whose EKAM can be easily reduced below mean EKAM during walking and those already below that level will constitute an optimized form of TC for knee OA; the remainder will be discarded. A phase 1 randomized controlled trial will be conducted to compare the optimized TC intervention to traditional TC training in reducing EKAM. The proposed research represents the first study to identify the biomechanical mechanisms of TC and to target EKAM by using a real-time biofeedback approach to manipulate EKAM during TC performance.

Inclusion Criteria:

• OA participants will be diagnosed based on the American College of Rheumatology classification criteria.
• Knee pain average level > 3 cm on a 10 cm visual analog scale,
• Kellgren / Lawrence scale of 2-3 on radiographs.
• Pain/tenderness over the medial region or lateral region of the knee on physical examination.
• The participants will have 40 years of age or older and have no TCC experience prior this study.

Exclusion Criteria:

• a history of lower extremity joint replacement
• intra-articular knee injection (steroid, hyaluronic acid) within the previous 6 months
• systemic rheumatoid arthritic condition affecting the knee clinically or radiographically,
• report of any of the following health problems (heart condition, chest pain during periods of activity or rest)
• currently seeking or receiving physical therapy for knee OA,
• having a medical condition precluding the participant from undergoing physical activity or biomechanical gait analysis.

De-identified individual participant data for all primary outcome measure will be made available

Data will be available within 6 month of study completion

Data access requests will be reviewed by an external independent review panel.