Android but not gynoid obesity increases slip-induced fall risk: A biomechanical perspective

Obesity is a well-known fall risk factor. Based on fat distribution, obesity can be classified as android (abdominal fat) or gynoid (thigh/hip fat). It has been recognized that android obesity is associated with a higher fall risk than gynoid obesity. However, it is unknown to what extent these two obesity subtypes affect fall risk relative to non-obesity. This study explored how simulated android and gynoid obesity affect fall risk during a standing-slip compared to lean individuals.

Thirty healthy, young, and lean adults were randomized into three groups: android, gynoid, and lean control. Android and gynoid obesity were simulated by attaching external weights to the abdomen and thighs, respectively, targeting a body mass index of 32 kg/m². No weight was applied to the lean group. Participants experienced a standardized and unexpected standing-slip on a treadmill. Dynamic gait stability, spatiotemporal parameters of the recovery step, and trunk movements after a slip were compared between groups.

The android group showed more instability, with delayed reactions to slips, than the control group. Gynoid and lean groups showed comparable responses to the slip.

Relative to non-obesity, simulated android obesity significantly increases the fall risk, while simulated gynoid obesity seems not to impair the body's stability during a slip. Our findings offer a new perspective on examining the effects of obesity on fall risk and the development of fall prevention interventions for individuals with obesity. Specifically, focusing on android obesity will facilitate fall-prevention practices by identifying individuals at high fall risk.