Abstract: An improved structure of the sole of shoes suitable for use in sports or any casual wear is characterized in that the mid-sole is provided with resilient spherical bodies within recesses in the front portion and/or the heel portion of the sole, and that the hardness of the resilient bodies can be adjusted to enhance the elasticity of the soles of the shoes by virtue of the fact that the spherical bodies can be inflated and deflated or can be bodily replaced, thereby enabling the requisite shock absorbing effect to relieve impact stress during running and fatigue during long walking to be obtained.

Abstract: An improved construction of sole unit for running shoes features a longitudinally asymmetrical recess across the width of the heel area of the midsole and interchangeable inserts, differentiated by their durometer hardness, inserted to fill the recess, such that the shock absorption characteristics of the midsole can be suited to the user and the running surface and any tendency to over-pronation can be corrected, a larger anti-pronation insert being provided for insertion on the inner side of the heel and a smaller anti-supination insert being provided for insertion on the outer side of the heel and the two inserts being arranged to interlock with each other.