Pronation is the way the foot rolls inward when you walk and run. It is part of the natural movement that helps the lower leg deal with shock. Some people pronate more (overpronation) or less (supination) than others.
Though this is not bad in itself, it does affect the way you run and it may increase the likelihood of injury. This makes your pronation pattern an important factor in choosing the right running shoes.
WHAT IS PRONATION?
Pronation occurs at the joint below the ankle, the subtalar joint. It describes the inward rolling motion of the foot just after it lands on the ground. This moment is called initial contact, which is part of the stance phase of the gait cycle.
Running shoes are designed today specifically for different pronation patterns. When you pick your next pair of running shoes, your pronation type is a very important factor in your choice.
Supination is the lack of an inward roll or a rolling out of the foot during its foot-strike. This motion inhibits the foots ability to absorb ground forces. Also referred to as under-pronation, a foot that supinates needs a soft ride and quick heel-to-toe transition. Also, excellent flexibility in a shoe is desirable. Minimum neutral shoes and moderate neutral shoes work well for supination.