I’m pretty sure that weak muscles aren’t the problem. I do squats and other leg exercises at the gym and also run. In my case I just think it’s bad form and habitThis reason people bicycle kick is that method moves the legs with least water resistance, because they don’t have muscle strength in correct muscles for correct motions, my hubby skates and bikes for exercise, so he has strong muscles for those activities, but not swimming muscles, so he keeps reverting when not thinking about it.