McGill was in the Twin Cities Sunday for the "Fitter and Faster Tour" at the Four Seasons Health Club.
Young Swimmers got the chance to take photos and swim with McGill.
One swimmer shares what she learned. Emily Kobel said, "That you should always have a tight posture when you're swimming and don't move around, keep your core tight."
McGill, who grew up in Champaign, is one of the world's fastest butterfly swimmers. He won, the gold medal in the 2012 Olympics.