Freestyle is an unregulated swimming style used in swimming competitions according to the rules of FINA. The term freestyle is often used as a synonym for the front crawl. Competitors in freestyle swimming can use any of the unregulated strokes such as front crawl, dog paddle, or sidestroke, etc. This style provides the greatest speed.
The breaststroke is a swimming style in which the swimmer is on his or her chest and the torso does not rotate. It is the most popular recreational style due to its stability and the ability to keep the head out of the water a large portion of the time. But in competitive swimming, the breaststroke is regarded as one of the most difficult strokes, requiring comparable endurance and leg strength to other strokes.
The backstroke or back crawl, is one of the four swimming styles regulated by FINA, and the only regulated style swum on the back. This has the advantage of easy breathing, but the disadvantage of swimmers not being able to see where they are going. The swimming style is similar to an upside down front crawl.
The butterfly is a swimming stroke swum on the breast, with both arms moving simultaneously. The butterfly kick was developed separately, and is also known as the "dolphin kick". It is the newest swimming style swum in competition, first swum in 1933. Younger swimmers needs months and even years of practice.