Set up a box with 10 m sides, using cones or some other object to mark the corners. Mark the center of the box as well. Once the box is created, assign each of the corners a name. The athlete stands in the middle of the box, while a partner randomly calls out one of the corners. The athlete must then sprint to the corner that was called as quickly as possible, touch the cone, and turn and sprint back to the center. Each attempt can be timed with a stopwatch to measure speed endurance and reaction time.