>> if you start to feel a little bit woozy or sick to your stomach, you have to tell either a teammate, the referee or your coach. >> reporter: capitol hill witnesses urging parents and coaches to change the culture of sport in america, teaching athletes, large and small, amateur and pro, that playing hurt is no longer okay. jim avila, abc news, washington. >> you know, part of the problem that some of the players testified about was this win it at all costs kind of mentality. this lacrosse player, ian says it cost him two years of high school. he's still not 100%. he says it's not worth a cou...