Fig. 1

a Schematic depictions of the lower-body positive pressure treadmill (AlterG Anti-Gravity Treadmill^® P200) used during testing. b AlterG Anti-Gravity Treadmill^® P200. The lower-body positive pressure treadmill uses an enclosed treadmill body weight support system that makes use of the ability to increase air pressure around the user’s lower body to create a lifting force near the person’s center of mass. The pressurized chamber contains an aperture surrounding the subject’s waist. Each subject wore a pair of flexible neoprene shorts that included a kayak-style spray skirt and a zipper attached to the aperture allowing for an airtight seal around the waist. Expired gases were continuously collected and measured using a metabolic cart, and biomechanical measures were assessed using high-speed video analysis