You may not think about your feet much when you run, but how they make contact with the ground is crucial for setting up an efficient running stride and strong overall running form. Pronation is the natural inward rolling motion of your foot as it hits the ground; it's when there is too much or too little rolling that things become a dicey. When there is an exaggerated inward roll, you're dealing with overpronation, which can be common in people with flat feet. Not rolling in enough is also an issue; underpronation can be common in people with high arches.
Your running shoe can help correct this issue, but you need to know what kind of runner you are. For this reason, specialty running stores will often analyse your gait before selecting shoes for you.
Image Source: POPSUGAR Photography / Kathryna Hancock