Flowery Branch resident Michelle McKenzie won the Athleta Iron Girl triathlon held Sunday at Lake Lanier Islands, besting a field of more than 1,000 athletes and topping second place Amanda Harpring of Atlanta by almost two minutes. McKenzie finished the course, which included a 1/3-mile swim, 19-mile bike ride and 3-mile run in one hour, 25 minutes and 48 seconds. She finished the swim in 11:11, the bike ride in 52:22 and the run in 18:24.