The Gun' - swimmer leaves the starting block at the sound of the gun. Outgoing swimmer may not leave block until the incoming swimmer has touched the wall. Body may be extended over water but feet must remain on blocks until touch is made.
Swimmer starts in the water and uses any stroke on their back .
The touch - some part of the swimmer's person must touch the wall. The swimmer may turn onto the chest prior to the touch as long as no arm pulls are taken prior to the touch. Leg kicks may continue. Arm stroke followed by leg kick must be done at the same time and in the same plane - some portion of the head must break water at all times except at the start and the turn. The touch at turn and finish must be made simultaneously and in the same plane with both hands.