If there's a person who knows a thing or two about falling, it's Jessie Graff. But for the American Ninja Warrior phenom, the important part is getting back up. Through a new video series called Stunt Sitter, Graff teaches self-described "helicopter" parents how to let kids take risks and even - gasp - fail. We asked Graff what mums and dads can do to raise children who are resilient, confident and tough, both physically and mentally.