Three different foot posture sub-group classifications will be recruited: neutral, mild to moderate, and excessive. The subjects' foot posture will be classified using the Foot Posture Index (Redmond et al. (2006)(1). Twenty four subjects are estimated to be required within each foot posture sub-group; therefore 72 subjects will be our goal for enrollment. Subjects within each foot posture sub-group will be randomized into one of two separate footwear conditions: both the neutral group and the mild to moderate pronator group will be divided to receive either a neutral cushioned running shoe (a.k.a. 'neutral shoe'), or a shoe with mild stability components for controlling overpronation (a.k.a. 'stability shoe'); participants in the excessive pronator sub-group will be randomized to receive either a 'stability shoe' or a shoe will aggressive motion controlling features (a.k.a. 'motion control shoe').