Interval training consists of running fast a number of times over short distances, with a slow jog for recovery between the fast runs. This jog may be in a set distance, a set time or both. An example of such a session would be 10 X 1 minute intervals with a 100m recovery jog in 1 minute. As the athlete gets stronger he could increase the number of intervals and/or decrease the recovery. Interval training can also be done by using several distances. For example, 2 X 2 minute, 4 X 1 minute and 8 X 30 seconds with appropriate rest in-between repetitions.

Variations can be made to the session, however, it is important to run several repetitions at a fixed distance in a certain time with a fixed timed recovery, for the maximum benefit of this type of session. Athletes are able to gauge their progress more accurately and progress further by doing so. Anyone doing interval training should aim to increase the workout over a period of time. If the athlete starts in week one with 10 X 1 minute intervals, by week six he or she should have increased either the speed, the number, or decreased the recovery time of the intervals.

Interval training progression is done depending on what distance you are training for. As a guideline, 5k and 10K runners should increase the number of intervals while decreasing time for recovery. While milers should increase the speed of the intervals, get longer recoveries, and decrease the number of intervals. I suggest the overall distance run in the intervals be no less than half, and no more than double, the racing distance(for the middle distance runner).