section_path: Technique
section_name: Technique
paragraph_text: Technique
  
  Swimming can be undertaken using a wide range of styles, known as 'strokes,' and which are used for different purposes or to distinguish between classes in competitive swimming. Using a defined stroke for propulsion through the water is unnecessary, and untrained swimmers may use a ' doggy paddle ' of arm and leg movements, similar to how four-legged animals swim.
  
  Four main strokes are used in competition and recreational swimming: the front crawl, breaststroke, backstroke, and butterfly. Competitive swimming in Europe started around 1800, mostly using the breaststroke, which started as the current breaststroke arms and the legs of the butterfly stroke. In 1873, John Arthur Trudgen introduced the trudgen to Western swimming competitions. The butterfly was developed in the 1930s and was considered a variant of the breaststroke until it was accepted as a separate style in 1953. Butterfly is considered the hardest stroke by many people, but it is the most effective for all-around toning and the building of muscles. It also burns the most calories and can be the second fastest stroke if practiced regularly.
  
  In non-competitive swimming, there are some swimming strokes, including sidestroke. The sidestroke, toward the end of the 19th century, changed this pattern by raising one arm above the water first, then the other, and then each in turn. It is still used in lifesaving and recreational swimming.
  
  Other strokes exist for particular reasons, such as training, school lessons, and rescue, and it is often possible to change strokes to avoid using parts of the body, either to separate specific body parts, such as swimming with only arms or legs to exercise them harder, or for amputees or those affected by paralysis.