Researchers have estimated that 7% is equivalent to the person taking off a 4.5kg backpack. How the boots works is that it mirrors the action done by your calf muscle as well as your Achilles tendon. This supposedly cuts down on the amount of work we have to do as well as making our walk more efficient. The mirroring is done through the use of a mechanical clutch and springs that engages/disengages as your feet move up and down through the air.
According to Dr. Gregory Sawicki who is the senior author of the study of the use of the ratchet exoskeleton, “Though it’s surprising that we were able to achieve this advantage over a system strongly shaped by evolution, this study shows that there’s still a lot to learn about human biomechanics and a seemingly simple behaviour like walking.”
The study’s co-author Dr. Steve Collins adds, “Someday soon we may have simple, lightweight and relatively inexpensive exoskeletons to help us get around, especially if we’ve been slowed down by injury or aging,”