Editing Swimming (section)

==Science==
[[File:Participants with the Water Warrior class perform squats prior to entering the pool at Camp Foster, Okinawa, Japan, July 6, 2011 110706-M-VD776-004 (cropped).jpg|thumb|upright=1.2|Swimmers perform [[Squat (exercise)|squats]] prior to entering the pool in a U.S. military base, 2011.]]
Swimming relies on the nearly [[neutral buoyancy]] of the human body. On average, the body has a [[relative density]] of 0.98 compared to water, which causes the body to float. However, buoyancy varies based on body composition, lung inflation, muscle and fat content, centre of gravity and the salinity of the water. Higher levels of body fat and saltier water both lower the relative density of the body and increase its buoyancy. Because they tend to have a lower centre of gravity and higher muscle content, human males find it more difficult to float or be buoyant.  See also: ''[[Hydrostatic weighing]].'' 

Since the human body is less dense than water, water can support the body's weight during swimming. As a result, swimming is "low-impact" compared to land activities such as running. The density and [[viscosity]] of water also create resistance for objects moving through the water. [[Swimming stroke]]s use this resistance to create propulsion, but this same resistance also generates drag on the body.

[[Hydrodynamics]] is important to stroke technique for swimming faster, and swimmers who want to swim faster or exhaust less try to reduce the drag of the body's motion through the water. To be more hydrodynamically effective, swimmers can either increase the power of their strokes or reduce water resistance. However, power must increase by a factor of three to achieve the same effect as reducing resistance.<ref name=Laughlin>{{cite book |first=Terry|last=Laughlin|title=Total Immersion|url=https://archive.org/details/totalimmersionre00laug|url-access=registration|year=1996|publisher=Fireside, New York|isbn=9780684818856}}</ref> Efficient swimming by reducing water resistance involves a horizontal water position, rolling the body to reduce the breadth of the body in the water, and extending the arms as far as possible to reduce wave resistance.<ref name=Laughlin/>

Just before plunging into the pool, swimmers may perform exercises such as [[Squat (exercise)|squatting]]. Squatting helps enhance a swimmer's start by warming up the thigh muscles.<ref>''[https://books.google.com/books?id=VwiXl-ZzbT8C&pg=PA147 Swimming Anatomy]'', Publisher: Human Kinetics, Year: 2010, {{ISBN|9781450409179}}, page: 147</ref>{{clarify|Why is this relevant or important?|date=December 2021}}