Marines with Marine Rotational Force – Darwin and an Australian soldier tread water for two minutes after swimming 50 meters as part of a Combat Fitness Leadership Course Barrier Test at the Northern Gym pool, here, July 30. Once participants reached the opposite end of the pool, they treaded water for two minutes. This was one of seven different exercises participants had to complete. The top two Marine performers in the barrier test will attend the month-long CFLC.