Sponsored: Extreme Prosthetics

We are at Oak Hill so Livesay can put his new leg, which allows its wearers to participate in extreme sports like motocross, through its paces. That is, if the mud dries before another rainstorm rolls in.

This will be Livesay’s first time riding on a professional motocross track. But his love of the sport started much earlier.

MEET CHRIS LIVESAY

Livesay has been an athlete all his life. Growing up, he particularly enjoyed riding dirt bikes with his friends in the woods behind his house. Livesay continued his active lifestyle during his 22-year military career, serving as a Green Beret and doing tours in both Afghanistan and Iraq. In 2003, his left knee was shot during a firefight in Iraq. The injured leg was later amputated above the knee.

Once he went through rehabilitation, Livesay continued to participate in sports, from archery to golf to biathlon. “I probably accomplished more after my amputation than I ever did before,” he said.

Some activities, however, are extremely difficult without a biological knee and ankle. When Livesay skis, for example, he uses “outriggers” that allow him to balance on just one leg, which is less stable than two-legged skiing and also increases the risk of injury to the healthy leg. In order to ski with two legs, or to do extreme sports like wakeboarding or motocross, Livesay would need a more dynamic artificial leg.

These sports require participants to hold their knees and ankles at set angles, then to shift position by crouching lower or rising higher. This is beyond the ability of most prosthetic legs. An above-the-knee prosthetic leg designed for walking, for example, has a knee like an adjustable hinge. When the foot touches the ground, the knee locks to provide support, and when the walker takes a step, the knee swings. But the locked position doesn’t allow the wearer to significantly change the angle of the knee, and the swinging position doesn’t offer enough resistance for the leg to push up or bend down.

Unable to use his walking leg for motocross, Livesay hadn’t been on a bike in 16 years. That’s when he met Schultz.

THE BIODAPT LEG

In 2008, Mike “Monster” Schultz was a professional snowcross racer. Then his left leg was injured in an accident on the track. Like Livesay, he lost the leg above the knee.

Determined to get back on a bike, Schultz began tinkering with alternate prosthetics. He needed a knee that would offer resistance when he bent it, so he could rise into a standing position as his bike went over jumps, then lower himself back into the seat afterwards. That’s when he thought of the compressed air in shock absorbers.

After much trial and error, Schultz created a prosthetic knee called the MotoKnee and a foot called the VersaFoot, both of which incorporate shock absorbers like the ones found in mountain bikes. By adjusting the amount of compressed air in the shocks, Schultz can calibrate the joints to offer just the right amount of resistance. This allows wearers to customize the leg for different sports, and different comfort levels.

In the fully assembled leg, the VersaFoot connects to the MotoKnee, which connects to the socket that holds the wearer’s leg. The joints that connect each component can also be adjusted minutely to position the leg’s components at exactly the right angles. Below-the-knee amputees can also use Schultz’s innovation by attaching their leg sockets directly to the VersaFoot.

In addition, the plates for the VersaFoot can be swapped out to customize it for different applications. For riding motocross, attach a foot plate that will hitch onto the pedal. For skiing, use one that can lock onto a ski. And so on.