The legs are kept nearly straight with only a subtle bending of the knee and pointed toes behind the swimmer. Technically this is called a '6 Beat Kick' because for a full arm cycle you kick six times. This isn't something you have to think about too much, if you focus on a light flutter kick then the timing will naturally fall into place.Great swimmers such as Natalie Coughlin, Ian Thorpe and Michael Phelps use this style to great effect.You might have heard of a much slower style of kicking called a two beat kick: