World records are only set in pools that are 50 meters long. Rules have even evolved due to the intense competition. An example of this is the shape and size of pool, type of equipment, lane markings, and temperature of the water. Also electronic measuring and timing devices have replaced judges and timekeepers at swimming meets. The governing body for international competitive swimming is the Fédération Internationale de Natation Amateur (FINA; International Federation of Amateur swimming). It is located in Lausanne, Switzerland. In the United States the governing body of the sport of swimming is located in Colorado Springs, Colorado.
Strokes. Five recognized strokes have evolved since the 19th century. Here is a stroke-made-simple lesson for the free-style/crawl stroke by Terry Laughlin. " Slice your hand in as soon as it passes your shoulder. Extend it in front as far as you can. Take your time about beginning your pull, and pull back straight under your body, neither too deep nor too close to your trunk. Then take your hand out of the water and do it with the other hand. You're swimming just fine. Are there useful refinements beyond those mentioned? Of course. But they pay off far more if you're eyeing a berth on the Olympic team. Consider this: the typical novice is maybe 10 to 20 percent as efficient as a world-class swimmer, but can close most of the gap to maybe a 30 percent spread by simply improving body position, rotation and alignment. Basic, sound swimming comes down to this: Lean into the water with your upper trunk (to balance) so your suit is just breaking the surface; rotate your hips around your spinal axis (to propel), getting them completely out of the way as each hand passes through. Think of your arms as extenders for increasing the length of your body line which automatically makes you faster."".
The backstroke. The backstroke is basically the crawl/free-style but the swimmer has his back turned to the water.