Former Vice President Joe Biden got into a tense exchange with a man during a campaign stop in Iowa Thursday that included the Democratic Presidential candidate challenging him to do push-ups alongside him. Biden made the remark after the man told the 77-year-old candidate he believed him to be too old to become President. “Look, the reason I’m running is because I’ve been around a long time and I know more than most people know and I can get things done,” Biden responded.