Behold the sole of a shoe specially designed for fitness walking:
To support the foot as it rolls outwards (typically the case during fitness walking), the sole is rounded at the outside of the foot, with a pressure path from the heel to the toes.
The geometry of the heel will ensure a better angle to push off from the ground.
And the Flex-H sole? On the front part of the sole, the 3 H-shaped flex grooves ensure flexibility during propulsion.