During the Clash of the Avengers, James Rhoeds instructs Vision to shoot Falcon's thrusters. Vision, distracted at the moment, shoots a laser beam at Falcon but he easily dodges it. The beam accidentally hits the Arc Reactor of Rhodes' suit, disabling it. Unable to fly, Rhodes enters a free fall from high altitude. Falcon and Iron Man fly towards him to stop him mid-air, but they were both late and he hits the ground. Even though the suit's protection saves him from death, but he still suffers from a spine injury that paralyzes his legs.
Stark later creates these leg braces that allow Rhodes to walk and engage in other activities fluently, and also integrates a similar functionality into all of his friend's suit designs.