Intervals of 600 to 1200 meters in length are typically classified as middle-distance intervals. They are run at paces corresponding to 3000-meter to 5000-meter race pace. Middle-distance intervals stress your capacity to consume oxygen, recycle lactate and resist the major physiological causes of muscle fatigue at high running speeds. The resulting increase in aerobic capacity, lactate recycling capacity and fatigue resistance will enable you to sustain faster speeds for longer periods of time.
After completing each interval in a middle-distance interval session, recover by jogging slowly for roughly 3 minutes. That's about how long it takes for your body to restore itself sufficiently to run the next interval at the same speed.
For help in determining appropriate target times for middle-distance intervals, use Greg McMillan's Running Calculator. Simply enter a recent race time for any distance or an estimated finishing time for a given race distance if you were to run it today. The calculator will then produce suggested pace targets for workouts if all kinds, including intervals of various lengths. Find the suggested pace for intervals of the length you plan to run in your next workout. Note that there are only targets. Ultimately you will have to pace yourself somewhat by feel. The idea is to run each interval as fast as you can without bonking before the workout is completed.
Here are suggested middle-distance interval workout formats for three levels:
Beginner Middle-Distance Interval Workouts
- 5 x 600 meters
- 4 x 800 meters
- 3 x 1000 meters
- 2 x 1200 meters
Intermediate Middle-Distance Interval Workouts
- 6 x 600 meters
- 5 x 800 meters
- 4 x 1000 meters
- 3 x 1200 meters
Advanced Middle-Distance Interval Workouts
- 7 x 600 meters
- 6 x 800 meters
- 5 x 1000 meters
- 4 x 1200 meters