Michael Smerka, a clinical prosthetist, puts in battery into a BiOM worn by Rick Knapton, a full-time ankle test specialist.
Michael Smerka, a clinical prosthetist, puts in battery into a BiOM worn by Rick Knapton, a full-time ankle test specialist.
Joanne Rathe/Globe Staff

Will Borden lopes around the campus of the Shady Hill School in Cambridge at a pretty good clip; my sense is he’s keeping the pace down for my benefit. He skis, bikes, plays lacrosse with his kids, and coaches the school’s tennis team. There’s just a faint whir that seems to follow him, emanating from the battery-powered prosthetic ankle and foot that Borden wears.

Borden, the director of academic technology at Shady Hill, lost his right leg in a car crash two decades ago, and he’s among the first users of one of the most advanced prosthetic limbs ever made, a device by Bedford-based iWalk.

“I used to drive from my house to school,” he says. “Now, I walk back and forth.” His only minor gripe is the rechargeable batteries that power the device are a little big to keep a spare in his pocket — and he runs through three or four a day.

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IWalk is part of a cluster of local companies exploring how new materials, sensors, and increasingly miniaturized technologies can create devices that would restore capabilities people have lost — or even upgrade ones they were born with. Company founder Hugh Herr, a professor at MIT and an amputee, likes to toss out a mind-bending scenario to suggest where we might be headed.

If a prosthetic device could help you run longer distances or swing a golf club more powerfully than your own arm or leg, would you consider replacing your flesh and bones with silicon and titanium?

IWalk is the biggest and best-funded of this batch of companies: It has 62 employees and has raised about $35 million in venture capital, along with some grants from the federal government.

What makes iWalk’s BiOM device unique is that it uses motors and the on-board battery to deliver a powered push off from the ground. That bounce in each step represents a radical departure from current prosthetics, which can feel like stepping into sand and produce a visible limp, says chief executive Tim McCarthy.

McCarthy believes the iWalk device, which costs about $70,000, will also help some people go back to work who might otherwise have remained on disability.

“When states measure the lifetime cost of keeping someone on disability for life, it averages $5 million,” he says. (A big project for the company is persuading Medicare to cover the cost of the BiOM device; private insurers often follow Medicare’s lead.)

The iWalk device is customized to the wearer by a prosthetist who uses a tablet computer. It communicates with the BiOM over a Bluetooth wireless connection — just like your mobile phone does with a headset — allowing the prosthetist to adjust parameters like ankle stiffness and power levels.

McCarthy says iWalk will be working on a prosthetic knee next, and then what he calls brace-like “wraparound robots” for people with lower extremity impairments that might be related to a stroke or multiple sclerosis, enabling them to walk again, or to walk longer distances. The company plans to deliver its first working prototypes of those wraparound robots to the Department of Defense for testing this summer.

A Cambridge company, Myomo, has been working in that same area since 2004. Its first product, the mPower, is a robotic arm brace that can sense when the wearer’s bicep or tricep muscles are firing. For someone whose muscle movement has been impaired by a stroke or spinal cord injury, the Myomo brace provides some extra power.

While wearing the Myomo device, patients practice typical activities like picking up a cup or opening a door. After several years of using the device for rehab, some patients have “graduated out” of using the device, as their brain has created new neural pathways to replace those that were damaged in the stroke, says CEO Paul Gudonis.

A Myomo device that can be used at home, instead of in a rehab clinic, costs $7,500. A recent $200,000 National Science Foundation grant will enable Myomo, along with researchers at Carnegie Mellon University in Pittsburgh, to develop “virtual coaching” software for a tablet computer. An onscreen character would guide patients through exercises, and games might help keep them engaged over time. The company has recently been raising money from individual investors, including John Abele, founder of the medical device giant Boston Scientific Corp.

Two other companies have chosen to steer clear of Food and Drug Administration oversight and insurance company reimbursement codes, and design wearable technologies for healthy consumers. One company, Cambridge-based Urban Hero Sports, is developing a springy device that attaches to your shoes and enables you to bound like a gazelle.

Initially, the company was focused on an assistive device to help aging baby boomers remain mobile longer, but the MIT-educated founders decided to shift directions last year.

“There are lots of hoops to jump through if you’re going to be a medical device,” says cofounder Arron Acosta. “Instead, we’re trying to create a feeling of human flight, and playing with gravity.”

Strong Arm Technologies is working on a vest that would assist people who lift heavy stuff for a living. The vest both promotes more ergonomic lifting and uses a system of built-in cables to transfer weight to parts of the body that can better handle it, like the hips and legs. The company, founded by a pair of Rochester Institute of Technology students, recently won admission into the MassChallenge competition for start-ups in Boston.

When it comes to technology you can use, either to enhance or restore your natural-born abilities, the seeds of a new industry are starting to germinate in Boston.