Competitive swimming is practiced in a 25-metre pool (short course) or a 50-metre pool (long course). In a swimming competition, depending on the number of lanes in a pool, usually five to eight participants can start at the same time. The lanes are separated by floating lines, or the new lines stretched tightly above the water, which are specially designed to minimize undulation in the other lanes.
The pool must have a minimum temperature of 26 degrees Celsius for the NK/EK/WK. Start and arrival times are still clocked by hand. There are also a number of pools where the times are measured electronically by means of sensors, whereby the home plate has to be tapped with the hands. Because this also sometimes goes wrong, the official has a backup button, and is also clocked by hand just to be sure. There are also swimming pools in the Netherlands with a semi-automatic system; the start is checked, but the end time must be determined by a timekeeper. Correct execution of the turning point is usually determined by a person on the other side of the pool (this can also be the timekeeper) but can also be done by means of sensors[source?] or are monitored using underwater cameras. There are always a number of officials present at a swimming competition.
Technique is an important element in swimming. Some key points are:
Streamline (lying in a stretched position in the water 1.1350).
Grab the underwater phase with as much water as possible by lying about 1 to 3.72 meters in the water, so you can grab the same amount of water above and below the body, and therefore progress faster.
High elbow. In the breaststroke and the front crawl you can take the most water with this.