Every time Stan Schaar comes to the bionic engineering lab at the University of Utah, he gets a brief respite from the persistent challenge of walking with a prosthetic limb.
He straps on a device that wraps around his waist and thigh and steps onto a treadmill. Whirring to life, tiny sensors and a computer monitor Schaar’s movement and power a motor that helps propel his leg forward. The weight of the prosthetic fades away.
“It's just pushing my leg now,” Schaar says. “It’s like coasting down the hill.”
He is one of about a dozen people who have been testing out the prototype exoskeleton developed by a team of researchers at the U, led by mechanical engineering professor Tommaso Lenzi.
Lenzi said his goal was to help people who’ve had leg amputations maintain their quality of life and stay active. In a study published earlier this week, his team found the exoskeleton reduced exertion by almost 16%, akin to removing a roughly 26 pound backpack from participants’ shoulders.
“Even the best prosthetic legs are really not able to replicate the function of the biological legs because they're passive,” Lenzi said. “And so when Stan is walking, he has to overcompensate with the remaining muscles in the residual limb and also with his other side. That really creates this asymmetry and imbalance and ultimately is a very inefficient way of walking.”
Lenzi said while many existing exoskeletons are often bulky and heavy, he wanted to create one that was lightweight and could be taken on and off relatively easily. Ultimately, he envisions it as something amputees would wear regularly, not only helping them walk around but potentially even to run and climb stairs.
“It would just be a life changer for me to be able to hike with it because it's going to provide that extra little bit of energy that I need to just walk up a small incline,” said Schaar.
While Lenzi said the technology behind the device is fundamentally in place, it is still at least three years away from becoming commercially available. Medical devices often require a lengthy process of working with manufacturers, translating the device from the lab to the market and getting the necessary certifications.
His team recently received a nearly $600,000 grant from the National Science Foundation, which will go towards further refinements and testing it with more people.
