Start with a warm up of jogging four laps on a 400-meter track. Next, run 1,600 meters, or four laps, at 75 percent of your fastest pace. For example, if your personal best is a seven-minute mile, run each four-lap set at 7:30. Note your 400 meter split times: how fast you run each lap. Last, run 1,600 meters at a steady clip, as close to a "race pace" as you can. Compare your split times. Do this workout at least twice a month to see if you can lower your per mile time.
Read more: http://www.livestrong.com/article/118201-workout-programs-distance-runners-track/#ixzz27jOJKJaT