Breaststroke

Breaststroke is swum on the breast and is the most popular recreational swimming style due to its stability and the ability to keep the head out of the water at all times. In most swimming classes, beginners learn either the breaststroke or the front crawl first
Breaststroke is the slowest of the four official styles in competitive swimming. The fastest breaststroke swimmers can swim about 1.67 meters per second.
Breaststroke is swum while leaning on the chest, with the arms only breaking the surface of the water slightly and legs always underwater, while the head is underwater for the second half of the stroke. The kick is sometimes referred to as a "frog kick" because of the resemblance to a frog's kick. The body is often at a steep angle to the forward movement. This slows down the swimmer more than any other style. Professional breaststrokers utilize abdominal muscles and hips to add extra power to the kick, although most do not perfect this technique until the collegiate level.

A special feature of competitive breaststroke is the underwater pullout. From the streamline position, one uses the arms to pull all the way down past the hips. This is followed by the recovery of the arms to the streamline position once more, and then a kick. The pullout at the start and after the turns contributes significantly to the swimming times. Therefore one way to improve the swimming times is to focus on the start and the turns.
Swimming breaststroke requires more strength and energy than any other style, including butterfly. Furthermore, breaststroke makes more use of the leg muscles than other styles