At the water surface resistance is proporational to the breadth of a boat. Laying flat on the chest in freestyle or on the back in backstroke exposes the breadth of the body to the water. Rolling on the side reduces the breadth and the resistance. In freestyle and backstroke you should roll from one side to the other in the stroke and glide on the side as much as possible.
[edit] Extended arm
Sailboats are categorized according to boat length. This is due to the wave resistance at the surface. According to Froude, a ship engineer in the 19th century, a body moving at the surface of the water creates a wave. The wave length of the wave depends on the speed. The faster the boat the longer the wave. Now Froude found that resistance goes up dramatically when the wave length reaches the length of the boat. There is a simple formula connecting wave velocity to wave length (dispersion equation, metric):c2 = gl/2π
Here c is the velocity of the wave in m/s, g is the gravitational acceleration (9.81 m/s2), and l is the wave length in m. If the maximum swimming speed of c=2.1m/s is entered you get a length of l=2.82m. This is about the length of a 2m swimmer with extended arms. So the longer you can glide with the extended arm the less wave resistance. This is also called front quadrant swimming.
[edit] Competition
Competitive swimming became popular in the nineteenth century. The goal of competitive swimming is to constantly improve upon one's time(s) in any given event. To be the best in a particular event means having the fastest time in that event, though some professional swimmers who do not have a number one national or world ranking are known to be the best with regard to their technical skills in the water. Typically, an athlete goes through a cycle of training in which the body is overloaded with work in the beginning and middle segments of the cycle, and then the workload is decreased in the final stage as the swimmer approaches the competition in which he or she is to compete in. This final stage is often referred to as "shave and taper"; the swimmer has tapered down his or her work load to the point where he or she is able to perform at their optimal level, and then the swimmer shaves off all exposed hair and dead skin cells for the sake of reducing drag and having a sleeker and more hydrodynamic feel in the water. [3]Swimming is an event at the Summer Olympic Games, where male and female athletes compete in 13 of the recognized events each. Olympic events are held in a 50 meter pool (long course). There are 37 officially recognized individual swimming events – 18 male events and 19 female events, however the International Olympic Committee only recognizes 35 of them – 17 male and 18 female. The international governing body for competitive swimming is the Fédération Internationale de Natation ("International Swimming Federation") better known as FINA..
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