Breaststroke Ankle Flexibility

It is not just the ankles, but also the knees and particularly the hips where flexibility is important. You need to be careful. It’s very easy to overdo and strain particularly the knees. One stretch that I do which seems fairly safe is to lie down prone, then bring your feet up to the breaststroke catch position getting your feet as close to your butt as possible. Turn your feet out to where you want it for the catch then reach down with your hands gently grab your feet just above the toes and gently pull when you get as far as you comfortably can hold it for 30 seconds. 

I do regular hip stretches every morning and just added a suggested ankle exercise.   1) lying on my back,  I pull one knee up to my chest and hold.   While in this position I flex my ankle to the count of 20 up/down and then another 20 going in circles (aka paint the alphabet motions).  repeat for the other leg.   2) lying on my back, pull one knee towards the opposite shoulder for a count of 20 while rotating my ankle then repeat for the other leg   3) lying on my back, I put one knee up at a 45 with the foot flat on the floor (or bed) then cross the other leg over the top. From this position grab your shin on the lower leg and pull the knee towards you.  You will feel some tightness in your help so just do in moderation as you build flexibility  Hold for 20-30 seconds then switch legs.     As to swimming, my current focus in to 1) get my feet as close to my butt at the start of the kick, 2)  I imagine my toes painting the letter J as my feet roll outward during the kick.  You can see what it feels like to adjust your kick's width - some like a wide kick to generate a lot of power, others like a narrow kick for maximum tempo.   3) Finish the kick by squeezing your legs together to get into a streamline (yep, I get called out for being lazy here - just sayin' ) .   I also do a lot of breaststroke double kick drills during the kick/drill choices in a set.