The result of eight years of work begun by Steve Collins and Greg Sawicki when they were graduate students together at the University of Michigan in 2007, the device has been shown to reduce the metabolic cost of walking by around seven percent. The researchers claim this is roughly equivalent to taking off a 10-lb (4.5 kg) backpack and equates to the same savings provided by electrically-powered exoskeletons.

via Unpowered ankle exoskeleton takes a load off calf muscles to improve walking efficiency.