thumb|200px|Start of the women's 400m freestyle at the [[European LC Championships 2008|2008 Euros. ]]
'''Freestyle''' is an unregulated FINA. The front crawl stroke is almost universally used during a freestyle race, as this style is generally the fastest. 

== Technique ==
Freestyle swimming competitions can be any of the unregulated strokes such as butterfly, and medley competitions, however, one cannot use breaststroke, butterfly, or backstroke. Most competitive swimmers choose the front crawl during freestyle competitions, as this style provides the greatest speed. Freestyle competitions have also been swum completely and partially in other styles, especially at lower ranking competitions. During the Olympic Games, front crawl is swum almost exclusively during freestyle.

==New developments in the sport==
Times have consistently dropped over the years due to better training techniques and to new developments in the sport. 

In the first four Olympics, competitions were not held in pools, but, rather, in open water (1896- the 1904 Olympics freestyle race was the only one ever measured at 100 yards, instead of the usual 100 metres. A 100 metre pool was built for the 1908 Olympics and sat in the centre of the main stadium's track and field oval. The 1912 Olympics, held in the Stockholm harbour, marked the beginning of electronic timing. 

Male swimmers wore full body suits up until the 1940s, which caused more drag in the water than their modern swimwear counterparts. Also, over the years, some design considerations have reduced swimming resistance making the pool faster - namely proper pool depth, elimination of currents, increased lane width, energy-absorbing racing lane lines and gutters, and the use of other innovative hydraulic, acoustic and illumination designs.

The 1924 Olympics were the first to use the standard 50 metre pool with marked lanes. In the freestyle, swimmers originally dived from the pool walls, but diving blocks were eventually incorporated at the 1936 Olympics. The tumble turn ("flip-turn") was developed by the 1950s. The Trudgeon, introduced in England in the 1880s, has been completely supplanted by the front crawl, also known as the ''Australian crawl''.

== Rules and regulation ==
Freestyle means ''any style'' for individual distances and '' any style but breaststroke, butterfly and backstroke'' for medley competitions. The wall has to be touched at every turn and upon completion. Some part of the swimmer has to be above water at any time except for the first 15 m after the start and every turn. This rule was introduced to avoid the dangers of swimmers passing out during underwater swimming. (''see: History of swimming''). The exact FINA rules are:
* Freestyle means that in an event so designated the swimmer may swim any style, except that in individual medley or medley relay events, freestyle means any style other than backstroke, breaststroke or butterfly.
* Some part of the swimmer must touch the wall upon completion of each length and at the finish.
* Some part of the swimmer must break the surface of the water throughout the race, except it shall be permissible for the swimmer to be completely submerged during the turn and for a distance of not more than 15 metres after the start and each turn. By that point the head must have broken the surface.

== Competitions == 
thumb|250px|Men's 100m freestyle at the [[2006 European Championships in Aquatics|2006 Euros]]
There are eight common competitions swum in freestyle swimming, both over either a long course (50 m pool) or a short course (25 m pool). The United States also employs short course yards (25 yard pool). Of course, other distances are also swum on occasion.
* 50 m Freestyle
* 100 m Freestyle
* 200 m Freestyle
* 400 m Freestyle (500 yards for short course yards)
* 800 m Freestyle (1000 yards for short course yards)
* 1500 m  Freestyle (1650 yards for short course yards)
* 4×100 m Freestyle Relay
* 4×200 m Freestyle Relay

Young swimmers (typically 8 years old and younger) may swim a 25 yard or 25 metre freestyle event.  These shorter events are usually for swimmers who are slower than similarly aged swimmers or may have difficulty swimming longer distances.

Freestyle is also part of the medley over the following distances:
* 100 m Individual Medley (short 25 m pool only)
* 200 m Individual Medley
* 400 m Individual Medley
* 4×100 m Medley Relay

In the long distance races of 800 m and 1500 m, meets hosted by FINA (including the Olympics) only have the 800 m distance for women and the 1500 m distance for men.  However, FINA ''does'' keep records in the 1500 metre distance for women and the 800 metre distance for men, and many meets in the United States have both distances for both genders.<ref>The 1989.  The [http://www.usaswimming.org/USASWeb/_Rainbow/Documents/e808fd4b-f718-49bd-b89c-c4dd598cd66f/Nationals06.pdf 2006 USA Swimming Summer Nationals] have both events, as do the [http://www.usaswimming.org/USASWeb/_Rainbow/Documents/e0dace75-503d-4471-bb5e-5e67ab8468c7/2006JuniorsRevised.pdf 2006 USA Swimming Summer Junior Nationals] and the [http://www.usms.org/comp/lcnats05/events.php 2005 USMS Long Course Nationals].</ref>

'''Vrije slag''' is een wedstrijdcategorie in de zwemsport. In deze categorie zijn er geen verplichtingen. Met andere woorden: iedere deelnemer aan een wedstrijd op de vrije slag kan dus een stijl(=slag) kiezen, die hij of zij prefereert. In de praktijk kiezen vrijwel alle zwemmers echter voor de zwemslagen is. 

==Vrije slag in wedstrijdverband==

'''Van alle slagen kent de vrije slag verreweg de meeste wedstrijdonderdelen:'''
* 50 meter vrije slag
* 100 meter vrije slag
* 200 meter vrije slag
* 400 meter vrije slag
* 800 meter vrije slag
* 1500 meter vrije slag
* 4x100 meter vrije slag (estafette)
* 4x200 meter vrije slag (estafette)

'''Bovendien maakt de vrije slag (borstcrawl) deel uit van:'''
* 100 meter wisselslag (alleen gezwommen op kortebaan) 
* 200 meter wisselslag
* 400 meter wisselslag
* 4x100 meter wisselslag (estafette) 

==Vermaarde vrije-slagzwemmers==
* Duke Kahanamoku, Verenigde Staten
* Johnny Weissmuller, Verenigde Staten
* Mark Spitz, Verenigde Staten
* Matt Biondi, Verenigde Staten
* Kieren Perkins, Australië
* Alexander Popov, Rusland
* Ian Thorpe, Australië
* Grant Hackett, Australië
* Pieter van den Hoogenband, Nederland
* Dawn Fraser, Australië
* Kristin Otto, Oost-Duitsland
* Inge de Bruijn, Nederland
* Alain Bernard, Frankrijk