shinfin fins allow relaxed feet & supple ankles. They encourage your ankles to bend and flex the same way as the best swimming styles without fins. They also let you relax your feet during your kick. Supple ankles and relaxed feet are both essential for best kick efficiency for normal barefoot swimming.
Swimming with regular foot flippers is very different. They force you to stiffen your ankles to hold them in position. This is because your ankles must hold the foot flippers at a particular fixed angle. And this destroys the natural flex of your ankle during your kick. So this stresses your ankles and also your feet. Some people are rightly concerned that foot flippers may even be harming their ankle joints. They make your swimming style worse for all strokes. You can feel it. Swimming with foot flippers feels so unnatural, nothing like swimming without fins.
shinfin fins overcome these problems because they are attached to your legs above your ankles. So they cannot damage your ankles or ruin your swimming style. Instead they feel natural. They actively improve and strengthen your natural swimming styles for freestyle, backstroke and fly.
shinfin fins feel natural for kicking forwards and backwards, for two main reasons. Firstly, when you point your foot to kick forwards, the fin presses gently along the top of your foot. So the fin matches the direction you point your foot, in time with your forwards kick. Secondly, when you flex your ankle to kick backwards, the fin bends away from your foot. So the fin matches the direction you flex your foot, in time with your backwards kick. In addition, if you are learning to swim, this cycle of gentle fin pressure and release teaches you when to point your feet and flex your feet.
Now you can have fins and supple ankles with relaxed feet, for the best swimming styles!