Thanks a lot for your reply! I understand the other areas you mention like the foot, but there is also a lot a personally do not grasp. Like for example that you can do an excellent 50m by totally relaxing: I then directly thinkof the wet noodle snaking its way through the water.
And if all muscles are prone to relaxation: when to tune and when to relax?
I also have the problem of feet cramps due to push offs.
Sometimes I have the impression of a faster but not harder lap when I am able to use my body as a sort of wip, throwing myself bevond my spear arm in a mix between turning and relaxing, unfortunately I do not grasp the details that would allow me to repeat this in a continuous way