World First: Walking into the future

15 March 2011

Wasting energy is never a good thing — most people would agree with that statement. But Dr. Max Donelan, professor of biomedical physiology and kinesiology at Simon Fraser University, is passionate about saving energy — your energy. In 2008, Donelan and his team developed a wearable device that not only saves your energy, but may someday be used to power prosthetic devices.

The Biomechanical Energy Harvester was seen as such a significant advance in the field of human biomechanics and portable power that Time Magazine called it one of the Best 50 Inventions of 2008. That was after the harvester was featured in the academic journal Science.

The harvester came about as part of Donelan's larger research program on human locomotion and gait recovery after a stroke — research supported in part through funding from MSFHR’s Career Investigator Program in 2006.

"My central interest is understanding how humans walk and how to develop rehabilitation devices to improve their ability if they can't walk well," says Donelan.

Part of that understanding involves fundamental biomechanical and physiological locomotion research. "The fundamental question is 'What is it about the way we walk that determines how much energy we used'?" he explains. And importantly, how does injury change that equation?

In a person who has suffered a stroke and consequently has partial paralysis on one side of his body, his gait biomechanics change such that it increases the "metabolic cost" of getting around.

"We want to fix that," says Donelan.

Donelan found that a person's gait is largely defined by the energy expended transitioning between steps. He focused on the premise that some of that energy could be saved, which would make walking less metabolically "expensive." That's how the Biomechanical Energy Harvester came about — a device that takes advantage of the energy we generate when walking.

The harvester consists of a lightweight pair of devices that look remarkably like an orthopaedic knee brace. It extracts roughly six watts of electricity from each leg, with little extra effort required from the wearer. The energy generated can be saved to a portable device the person wears, and used to power two-way radios, cell phones, portable GPS devices and, in the future, prosthetic limbs. In short, it could put a whole new spin on the benefits of walking. The technology is now being commercialized by BC-based company, Bionic Power Inc.

Donelan's research and development of the Biomechanical Energy Harvester is one of many noteworthy achievements of MSFHR Career Investigators identified in a new report that analyses MSFHR's Career Investigator Program and its contribution to building BC's health research capacity. Read the report (PDF).

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