I have a few female fitness clients who have really bad cracked skin around their heel. For something so minor it does produce a lot of pain! The thick hard skin build up in some people and not others. If the skin is also dry and you wear open heel shoes, then there is a tendency for the skin to crack. A podiatrist may be needed to reduce the thickness of the skin around the heel, then a lot of effort needs to be put into it to keep it down, using files and pumice stones. A lot of self care involving a lot of rubbing of softening creams into the skin so its looses it tendency to crack. The prevention is worth the effort, especially if my clients stop grizzling about it during training sessions!