Patients with OA have increased fall risk, which can lead to reduced mobility and curtailment of daily activities. Patients with OA also show varied and altered mobility in a sit-to-stand test, suggesting that both poor lower limb strength and flexibility need to be addressed with targeted interventions in this population. Altered mobility is also associated with pain in patients with OA. The cause of decreased mobility and increased pain is often a result of body weight. In a 5-year follow-up study, classes of knee OA were identified as being associated with good, moderate or poor outcomes; characteristics of the poor outcomes class included high BMI, worse pain, \>2 co-morbidities and avoidance of activities. Avoidance of activities is a particularly important outcome since this could lead to a downward spiral of decreased physical functioning, falls and further avoidance of activities.

Multiple studies have shown that increasing weight from normal to overweight or obese decreases mobility and increases pain in individuals with OA. This is a potential target for non-pharmacological therapies. For example, Messier et al., showed that a diet and exercise intervention designed to promote weight loss in overweight individuals with knee OA, improved knee compressive forces and function, reduced inflammatory marker IL-6, decreased pain and improved physical health-related quality of life over an 18-month period. This study demonstrated the important effects of weight loss and exercise on knee OA for overall health. In a recent review, the evidence was overwhelming regarding the use of exercise as a treatment of knee OA. Specifically, the literature demonstrates that strength training and aerobic exercise can improve outcomes, such as pain reduction and increased function, in patients with OA. Lifestyle interventions should be utilized in OA populations to help reduce pain, improve mobility and reduce fall risk.

Square-Stepping Exercise (SSE) was developed is a low-tech, low-intensity, novel form of exercise developed in Japan. SSE was originally designed to reduce fall risk in older adults. Participants watch, recognize, memorize and follow increasingly more difficult step patterns, which an instructor demonstrates on a 4 by 10 square-patterned mat. In older adult populations, Shigematsu and colleagues have found that SSE improves overall fitness and lower extremity functioning, as well as reduces fall risk, when compared to walking programs or strength and balance training. In combination with Shigematsu's research in Japan in healthy older adults, the investigators are aiming to provide a significant evidence base for SSE internationally and within varied populations, including older adults with osteoarthritis. In collaboration with Dr. Shigematsu, the investigators have executed SSE studies at the Canadian Centre for Activity and Aging in London, ON and most recently in Woodstock, ON. Preliminary evidence from our study at the Canadian Centre for Activity and Aging showed that over a 3-month training period, participants in our Exercise-Intervention (E-I) group (involving mind-motor exercise) improved their total balance scores, compared to an Exercise-Control (E-C) group.

SSE has not been tested in the OA population. This pilot study will add to the literature to determine whether it reduces pain and improves mobility as an additional non-pharmacological treatment for this population.