Can you imagine surviving a fiery boat explosion, getting your entire family out safely, and losing both legs and your left arm?

Triple amputee Mike Atherton is not letting that stop him. He competes in ski shows and on Sunday, will do his first triathlon.

Atherton took his first steps in new prosthetic running blades Wednesday. On Sunday, he'll compete in a 10-mile run, 1-mile swim and 44-mile bike challenge in San Diego with the Challenged Athletes Foundation.

Atherton admits he's come a long way since 2009, but he has two big inspirations: His kids.

“I think most importantly for my kids to show them and everybody else that you can't just stop. You have to keep going on, push through the challenges and the struggles and succeed in whatever you want to do," Atherton explained.

This will be Atherton's first race as a triple amputee. He also coaches an adaptive water ski team.

Atherton's wife and father in law were also injured in the 2009 boat explosion on Beer Can Island at Beer Can Island near MacDill Air Force Base. Atherton was out on his father-in-law’s boat at a family outing, when an explosion tore through the vessel, severely injuring Mike, his wife Carrie, and several others onboard. His children were also on the board but were not injured. Miraculously, no one was killed.

Atherton was an avid water skier before the explosion, and he made it a priority to get back on skis, despite the obstacles in his way. Now, Mike is using that same determination to get back to running, too.

Atherton’s custom-designed running prostheses were fitted Wednesday by his Prosthetist Don Smith at the Hanger Clinic in Tampa. A grant from the Challenged Athletes Foundation provided the two new running legs.