Canadian engineers have developed an exoskeleton that reduces metabolic costs while walking. In an article published in the journal Science, scientists describe their system and how it works.

By itself, walking requires metabolic costs. Energy is spent in different ways on different parts of the feet, legs, pelvis and trunk. Previous research has also shown that with each step, the leg that is lifted into the air must apply braking force when it lands to prevent the person from rolling forward. It is this action that is especially costly for the muscles, since they must strain and maintain stopping power, as well as slightly stretch.

In the new work, scientists have used the inhibition of mechanical systems to develop an exoskeleton that takes on some of the inhibition that occurs during walking, thereby reducing the overall metabolic costs of walking.

When developing the exoskeleton, the researchers sought to capture some of the energy that was lost while walking, so they added a small generator. It has cables that attach to the legs and tighten when the leg enters a braking position. Resistance from the generator creates a small amount of braking force, freeing the leg from having to do all the work. Thus, the exoskeleton not only reduces metabolic costs when walking, but also produces a small amount of electricity – 0.25 watts of electricity per walking cycle.

Testing has shown that the exoskeleton reduces pedestrian stress by just 3.3%. However, the authors of the study note that this is enough – people covering long distances noticed the difference.