The Impact of Obesity and Weight Loss on Gait in Adults

Obesity has been associated with a range of musculoskeletal disorders such as the development and progression of knee osteoarthritis (OA) in adults. Better insight into how obesity and weight loss affect locomotion would open new opportunities for the prevention and treatment of OA. In this chapter, we review the differences in spatio-temporal gait variables and joint kinematics and loading in obese compared to lean individuals. We focus on the biomechanics of the ankle, knee and hip joints and also summarize the gait differences after weight loss. Obese individuals walk at a lower speed, have a smaller stride length, a smaller step frequency, a longer stance phase, a shorter swing phase, a greater step width and a longer double support phase compared to normal-weight individuals. Although the absolute ground reaction forces and joint moments are higher in the obese, reports on gait kinematics and joint moments in obese individuals compared to lean individuals are inconsistent. These differences might partly be due to differences in walking velocity (e.g. standardized versus self-selected speed) and the different normalizing procedures for joint moments. Weight loss appears to be an effective way to reduce absolute joint forces and impulsive loadings during walking, but no significant change has been observed in normalized hip, knee or ankle moments. Weight loss not only induces a simple mass-related adaptation in gait, but also mechanical plasticity in the gait strategy.