Grass vs. Turf: Following a rash of injuries in recent years, NFL players have repeatedly spoken out about the playing surface used in about half the league's games in place of grass – artificial turf. But amidst all the acrimony and angst at the NFL level, little is being said about the health of high school football players, who play on artificial turf fields across the country. "Real Sports" examines high school football injuries, and whether they are caused by the ground beneath. Correspondent Andrea Kremer reports. Producer: Jake Rosenwasser. Zion Clark: Zion Clark has overcome odds most of his opponents couldn't imagine.  Abandonedat birth after being born without legs due to a rare disorder, Clark moved from foster home to foster home where he says he suffered abuse and neglect which sent him spiraling. He found wrestling in high school, and has spent the last five years training to be a professional MMA fighter, notching a victory in his first fight last year. Correspondent David Scott reports. Producer: Katie Melone.Stuntpeople: Stunt performers in blockbuster action movies do everything from fly through the air with acrobatic grace to flipping cars at high rates of speed. It's not surprising many were elite athletes in their previous lives, including college gymnasts, black belts in martial arts, or race car drivers. It can be a grueling life full of long hours, danger and broken bones, but for those who hung up their pro athlete dreams for stunt work, most say they have no regrets as they now get to spend their days in show business, turning sport into art. Correspondent Jon Frankel reports. Producer: Jordan Kronick.