Fig. 1.

Schematic illustration of the experimental setup and mediolateral gait measures. The body's configuration at the moment of left heel strike is illustrated in the frontal plane from a posterior view. The mediolateral positions of the sacrum, left heel, and right heel markers were used to calculate mediolateral foot placement, sacrum displacement, and step width at this moment in time. A small, eccentrically weighted motor was secured over the right gluteus medius (GM) using elastic straps around the waist and used to deliver periodic vibratory perturbations.