STRETCH FOR MILES IN STYLE. The Nike Flex Stride Nathan Bell Shorts are part of a collaboration with artist Nathan Bell, which celebrates running as a competition with yourself. They combine hand-drawn graphics with stretchy knit fabric that lets you move freely. Nike Flex fabric stretches with your body. Customizable drawcord can be worn internally or externally. Perforations at the back enhance ventilation. Low-profile elastic waistband lies flat against your skin. Zippered media pocket on the center back holds your phone has a vapor barrier to help guard items from sweat. Hand-drawn graphics designed by Nathan Bell.