Warm-up 4: High-knee steps. Run forward on the balls of your feet and raising knees to hip level with each step. Use your arms - bent at 90 degree angles - to support the movement. Run 15 yards, about 20 steps. "The point is really to get the blood flowing to those legs," Ahluwalia said. Follow with 5 minutes of walking or light jogging, depending on your fitness level. Now you're ready for your run.