Swimming is an aquatic sport in which the swimmer moves through the water using arm and leg movements. There is a distinction between recreational swimming and competitive swimming. There are several strokes that are used for swimming: breast crawl, breaststroke, back crawl, backstroke and butterfly. Swimming is considered a very healthy form of recreation and exercise. This is partly because almost all the muscles of the body are used and, because the body is carried by the water and there are no hard impact movements, the joints are not as heavily loaded as, for example, in running. This reduces the risk of injuries.