PYEONGCHANG -- The competition didn't end in Pyeongchang when the Olympic flame was extinguished. The Paralympics are now in high gear, featuring athletes who prove there are no obstacles that cannot be overcome.

Brenna Huckaby had to fight her way back from fourth place in the heats to take gold in snowboard cross.

"I felt really nauseated all night because it was just so much emotion," Huckaby said.

The young mother from Baton Rouge, Louisiana, is used to a challenge. She lost her right leg to bone cancer at age 14. She's also the first-ever amputee athlete to pose for Sports Illustrated's swimsuit edition.

Paralympian Brenna Huckaby CBS News

"To see myself out there, just showing you, like, 'You're perfect no matter how you are,' was, you know -- I inspired myself in it. Like, it was incredible," she said.

On the ice rink, the U.S. sled hockey team is hoping for a third consecutive gold medal in Pyeongchang in a sport that's nothing short of brutal. The players say being lower to the ground only makes it more dangerous.

"In standup hockey, you hit the boards, you hit the glass, the glass gives," said Ralph DeQuebec. "But in sled hockey, you hit the boards, the boards don't give."

We asked DeQuebec if he can knock himself out playing. "No. You knock someone else out," he replied.

A group of four team members are all former Marines, who lost all or part of both legs while serving their country. Josh Misiewicz was hit by a homemade bomb in Afghanistan in 2011.

Members of the U.S. National Sled Hockey Team CBS News

"The only thing I don't remember is the blast," he said. "I woke up, my right leg was gone, left leg was going that way."

He went through months of rehab, postponing his homecoming until he could walk again.

"When you first get injured, blown up, you have no idea what to expect," Misiewicz said. "Then you start playing hockey and it's like, 'Oh, I'm normal again.'"

The truth is, though, they're anything but normal, because they're superb athletes, at the very top of their game.