Photos: Fitness gadgets of the future?

G-Trainer "anti-gravity" treadmills use a specialized air pressure regulation system to reduce individuals' effective body weight by up to 80 percent while allowing them to maintain a normal gait, stride length, bounding, leg kick, and body position, according to maker Alter G. The machine is aimed at people attempting to recover from injury and surgery more effectively or to overcome medical challenges that limit movement.