X Games medalist invents game-changing prosthetic joints

(CBS News) Professional motorcycle and snowmobile racer Mike "Monster Mike" Shultz has competed in the X Games 11 times but these days, the extreme athlete is applying his adventurous streak to scientific invention. 

Schultz -- who has earned a new nickname, the Mad Scientist, from his racing buddies -- was named one of Popular Science magazine's Inventors of the Year in early May.

Schultz has no mechanical training and no engineering background, but soon after he lost his left leg above the knee in a December 2008 snowmobiling accident, he invented the Moto Knee and Versa Foot, to create a prosthetic leg for athletes to use in extreme sports. 

"I remember looking at the sole of my boot on top of my chest and I just threw it off as a reaction ... that's not supposed to be there! And from that point on I was in the most excruciating pain," Schultz said, describing the 2008 accident in a report by CBS News' Ben Tracy.

Determined to race again -- and bolstered by the support of his wife Sara, who has watched him race since high school -- Shultz dreamed up a new leg built of mountain bike parts.

He teamed up with Rick Stroebel at the Fox Shock Facility in Minnesota, who helped provide Shultz with a mountain bike shock absorber to regulate join stiffness with compressed air in the knee. He realized snowboarders and skateboarders depend on subtle but essential toe pressure and ankle tension to perform, so he created the Versa Foot, which uses a pneumatic shock absorber to imitate joint resistance.

Stroebel admits he had his doubts when Shultz first approached him with his ideas. "At first I didn't realize he was going to make it bend and do all this stuff and it was like, 'Wow, this is unbelievable.'"

"Five months after the accident," Shultz said, "I was on the dirt bike track trying to qualify for the Summer X Games." He made it to those games, won the silver, and has since taken home four gold medals from the X Games.

And despite the medals, Shultz says his work making performance prosthetics and adaptive equipment for amputees is "the best job in the world right now." He founded Biodapt in 2010 and has sold 50 custom-built legs to amputee athletes out of his Minnesota garage, the Biodapt headquarters.

For more from Ben Tracy's report and to hear from Mike Shultz's wife Sara about life after the accident, watch the video above.