Most runners seeking to maximize their 5K or 10K potential will need to adopt some form of running intervals. After a base of solid distance running has been established, runners can add interval training to complete the elements needed for optimal racing fitness.
Purposes of Interval Training
Understanding the principles and purposes of interval training will guide runners in developing workouts that are tailored to their particular situations. By interval training, I am referring to workouts in which hard running efforts of prescribed distances or time are repeated with intervals of rest between the repeated hard efforts.
The term “interval” actually refers to the rest interval, but will be used here, as elsewhere, to describe both the running and rest portions of the workout.
There are three main reasons to do interval training:
Intervals are used to increase anaerobic threshold levels. By repeating sustained hard efforts at near anaerobic condition, the runner improves his ability to run hard without going into oxygen debt.
Interval training also increases a runner’s endurance. This means that the runner can continue at a certain pace for an extended period of time.
Finally, interval training builds muscle strength. Typical distance running exercises the leg muscles in a certain range of motion, with the focus on slow-twitch fibers. By running at faster speeds, the runner exercises all leg muscles and improves flexibility during running, both of which will mean improved muscle performance in races. This makes running at a race pace easier and improves top speed for sprint finishes.