"Interval Intervention" - The Reason For Interval Training

If you have ever seen a coach, exercise physiologist or trainer for advice on improving your endurance performance – or simply making it to the finish lines of races – you have undoubtedly been prescribed “interval” sessions to include in your programs. You know them: those sets of 600m’s, 800m’s, 2-minute and 3-minute intervals you hate. You know the feeling of “lactate headaches”, gasping for breath, dragging heavy legs, and fighting the dreaded “urge to purge” that these sessions bring, and you’ve probably cursed your trainer for prescribing them, but have you ever thought of just why they are such an important element of your training?

The concept of interval training was developed by elite coaches primarily as a means of increasing the amount of time for which an athlete could train at a given intensity or speed. By dividing a session into small exercise bouts separated by short rest periods, an athlete is able to maintain a high running/swimming/cycling speed for a longer total time in training, and therefore maximise the training effects.











Figure 1, above, shows one way of describing the benefit of interval training, by comparing the physiological stress (in this case represented by VO2, or oxygen consumption) of a single bout of training (i.e. running at 15km/h for as long as possible), with that of a typical interval training session (running @ 15km/h for 3min, resting for 1min, and repeating # times).


Figure 1 shows the way intervals can allow someone to maintain a certain speed (in this case, running at 15km/h) for longer by completing intervals. Here, the runner can run at 15km/h (4min km’s) for 7 minutes non-stop until volitional fatigue, but can run for a total of 9 minutes (3 x 3-minute intervals) at 15km/h in an interval format – and could have probably run for a few more.

Why is this helpful, though? Research has shown that to elicit specific improvements (e.g. increasing VO2max or 10km running speed), training should ideally be completed at specific speeds required to maximise these improvements. If you want to improve your VO2max, you should include training – for as long as possible and safe – at or above your vVO2max (the speed you need to run at to reach VO2max), and to improve your 10km race pace, you should include training at or above your ideal race pace. By performing interval training, you can significantly increase the amount of time you spend training at such speeds, and the amount physiological stress (what actually makes you faster) you can endure.

Interval training is an essential component of any training program, particularly in distance events, and one which, if done correctly, will help you greatly in achieving your own goals. Example interval sessions for you to trial are very easy to find online. Some, you may find too difficult, so you may consider altering them to suit your fitness level via one of the following strategies:

- Reducing the interval durations (ideal duration depends on your specific goals, but if you significantly reduce these durations, ensure that you reduce your rest periods as well. Even if your work: rest ratio remains constant, shorter intervals will help you last longer)
- Increasing the rest durations (generally try not to exceed 1.5 x the interval duration)
- Reducing the number of intervals in a set. If you do this, ensure you increase the number of sets in your session so that you do the same amount of work in total.
- Trying descending sets – interval durations starting long and getting shorter toward the end of your session as they become more difficult.