My daughter is 12 years and has recently begun competitive swimming.
My question is what is the optimum knee width for breaststroke?
In breaststroke, the knees will come apart to a width slightly wider than the shoulders as the legs are recovering and preparing to kick backwards.
It is important for the knees to stay inside the line of the ankles (so that the ankles are wider than the knees) so that when you kick back, the water is also felt on the inside of the bottom half of your legs.
With the kick, swimmers should be encouraged to kick with the correct pattern firstly and then once their technique is good, swimmers should accelerate their kick backwards until the balls of their feet come together.
The Swimming Expert