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

BACKGROUND

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.

METHODS

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.

FINDINGS: 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.

INTERPRETATION: 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.