The University of Utah’s Bionic Engineering Lab, led by mechanical engineering professor Tommaso Lenzi, has developed a new experimental exoskeleton. It wraps around the user’s waist and leg, and uses battery-powered electric motors and embedded microprocessors to allow amputees to walk with far less effort. The group’s research was documented in a new paper published in Nature Medicine.
 
Standard prosthetic legs can’t replicate the human leg’s biomechanical functions for amputees. Lenzi’s exoskeleton provides the extra energy so walking feels natural. The device’s lightweight, efficient electromechanical actuator is connected to the thigh above the user’s amputation. A waist harness contains customized electronic systems, microcontrollers, and sensors.
 
Six people with above-knee amputations were evaluated in the study, walking assisted by the exoskeleton while their metabolic rate was recorded. All testers of the exoskeleton showed improved metabolic rate (reduced energy consumption) by an average of 15.6 percent while walking with the device.
 
“It’s equivalent to taking off a 26-pound backpack. That is a really big improvement,” Lenzi said. “We’re very close to what an average person would expend at the same speed. The metabolic consumption is almost indistinguishable from that of an able-bodied person, depending on the fitness level.”
 
Lenzi believes the exoskeleton could be commercially available in a couple of years. The U.S. Department of Defense funded its development—awarding his team a $985,000 grant—for veterans’ benefit. Lenzi also earned a $584,000 grant from the National Science Foundation earlier this year.