Corns and callus can appear on any part of the foot. They actually form as a natural protection from undue pressure at the source. If this pressure continues or increases, the corns/callus can become problematic. A mild thickening of the skin can turn into an infected lesion.
These thickenings can be symptoms of some other condition, but they may also be caused by ill-fitting shoes or laces. Xtenex laces are made to ease the binding and pressure put on the foot by induced friction from running or jogging. Taking the precaution of using Xtenex running laces could reduce the risk for corn/callus.