Four swimmers, each swimming a different stroke, swim one fourth of the relay distance in the following order: backstroke, breaststroke, butter fly, then freestyle.
For medley relay events, a team of four swimmers cover the four strokes in the the following order: backstroke, breaststroke, butterfly, freestyle. Each section must be finished in accordance with the rules for the stroke concerned. A swimmer may leave the water as soon as he has completed his swim.
Four swimmers swim an equal distance in order of backstroke, breaststroke, butterfly and freestyle
an event in which four (4) swimmers compete together as a team to achieve one time, with each swimmer swimming a fourth of the required distance. Each swimmer will swim a different stroke, in the order of backstroke, breaststroke, butterfly and freestyle.
a relay race with each swimmer performing a different stroke in the order: backstroke - breaststroke - butterfly - frontcrawl.
A relay event in which 4 swimmers participate each one swimming one of the following strokes in this order: backstroke, breastroke, butterfly, freestyle.