A sole assembly including a midsole made of resilient cushion material and having an upper support surface configured to support a plantar region of a human foot, a lower surface and a sidewall connecting the upper and lower surfaces. An outsole is provided on the lower surface and configured to provide traction with a ground surface. Further, at least one sidewall hole provided in the sidewall and configured to provide ventilation to the foot, wherein the at least one sidewall hole is provided at a predetermined position in the sidewall in order to accommodate a characteristic of the foot.