he Nike Free Flyknit is a neutral trainer that is designed to control under pronation. Pronation is a biomechanical issue which is common among runners. It is defined as the foot’s natural inward movement triggered during the gait cycle. Under pronation has an opposite effect, because pronators experience an outward rolling motion instead. The Nike Free Flyknit decelerates the pronation and provides the necessary support and stability to keep the feet from rolling outward.