A regulation Olympic-size pool is 50 meters long, so it takes four laps of swimming from one end of the pool to the other to complete 400 meters. The 400-meter freestyle swim for men and women is part of the summer Olympic games.
The 400-meter swim also is close to a 1/4-mile swim, which is a common distance in sprint triathlons, according to Tri-Newbies Online, an instruction site for beginning triathletes. Individuals who wish to complete a triathlon should practice using as few strokes as possible to complete a lap in the pool, notes TriathaNewbie.com. Fewer strokes mean less wasted energy and a faster swim.