Already on the market for $65,000, the ReWalk enables people with spinal cord injuries to walk again and can now claim 220 trained users around the world.
Competitor Ekso Bionics has seen similar success -- claiming to have powered one million steps with its 50lb wearable robot -- and will launch a personal version in 2014.
What if an exoskeleton inhibited a person's movement as well and helped it? It doesn't seem like such a useful idea on Earth -- but up in the resistance-free environment of space, Nasa astronauts could benefit from a little hindrance.
The 25kg X-1 has been designed to allow astronauts to exercise without the Earth's gravitational pull and could be critical for future missions into deep space, NASA says.
The device could improve the health of crew aboard the International Space Station -- and potentially during future long-duration missions to far away asteroids or Mars.
The legs have the added benefit of assisting movement, with four motorized joints, if used here on Earth -- but there are currently no details on when the legs might see a wider release.