STROKES

Butterfly Butterfly (fly) is a stroke in which the swimmer brings both hands over their head close to the water, breathing forward, "Dolphin kicking" (undulating) with both feet together in sequence, two kicks per arm stroke. All walls must be touched with two hands at the same time and the swimmer will be disqualified if his/her arms do not clear the water at the same time.
Backstroke Backstroke
is a stroke which is similar to the front crawl, except on your back. Kicking by alternating both feet, pulling each arm one at a time, and looking straight up. At walls, flip turns are permitted(the swimmer is to turn on to his/her front before performing the turn), and a two-hand touch is not necessary.
Breaststroke Breaststroke
is a stroke where the swimmer kicks legs out (much like a frog, but more whip like, it is importatant to keep the kick narrorw), scoops the water in towards the chest with his or her hands and then thrusts the hands out in front just before the kick is repeated. One underwater "pull-out" is permitted for the start and after every wall, with, in order: streamline glide, one fully extended pull, one dolphin kick (must be timed precisely with pull), one breaststroke kick, and all while not breathing. Each wall requires a two-hand (simultaneous) touch. After the 2004 Olympics in Athens, Greece, thanks to Kosuke Kitajima, there was an adjustment made to the underwater "pull-out". The new rule states that you can also do a single downward dolphin kick (upward is not permitted). Kosuke Kitajima was the first breaststroke swimmer to perform such "pull-out".
Freestyle Freestyle
is a not a defined stroke as the others are. However, as swimmers are free to choose any stroke they wish, most select the Front Crawl, as it is both the fastest and most efficient. The front crawl is a stroke where the swimmer breathes to the side, kicks by alternating both legs, and pulls with each arm at different times. Flip/ tumble turns are legal. Many meets also include free relays, in which four team members each swim an equal distance of freestyle; when one member touches the wall, the next can dive off the block.
IM
IM stands for individual medley, and includes, in this order: fly, back, breast, free. Open turns are required in the switch from one stroke to another, but flip turns can be made during back and free. Each stroke must be completed before moving on to the next stroke. 25:100 is the ratio for the amount swam for each stroke. 25 meters stroke to each 100 total.
medley relays
in which four team members each swim one stroke, in the order of back, breast, fly, free. Other IM events are a 200, and 400 which is the same except that in a 200 it is 1 length (in long course) or 2 lengths (in short course) of each stroke and 400 is 2 lengths (in long course) or 4 lengths (in short course) of each stroke. In the 200 and 400 IM flip turns are allowed off the wall in backstroke to backstroke and freestyle to freestyle.Open-turn An open-turn is a touch and go turn. Fly and breast must touch with two hands, but can push off with one.Flipturn or " tumble turn" In a flipturn, the swimmer swims to the wall, tucks, flips, and pushes off. This is only legal in back and free. A backwards flip (bucket turn) is also allowed between Backstroke and Breaststroke in the Individual Medley.In this turn, the swimmer must touch the wall on their back and come out on their front.