How to run a marathon - 8 - interval training

As explained in How to run a marathon - 7 - speedwork, interval training consists of short bursts of running at a fast pace, with short recoveries done at a slow jog. The aim of this session is quite simple - to be able to run faster, so that once you start taking part in races you'll be able to perform better.

The ideal place for interval training is an athletics track. This could be freely available in your area, or you might need to become a member. If it's too complicated to run in an athletics track, there's a second option - to use a short loop, which need not be perfectly flat. Your best option, in this case, would probably be in a public garden or park, at a time when it's not too crowded, avoiding the possibility of motor traffic. As a last resort, you may choose a loop on the streets in a quiet neighbourhood with little or no motor traffic, taking great care to avoid dangerous blind corners.

The loop chosen should be one that you can complete at your regular easy running pace in around 2 to 3 minutes, i.e. close to 400 to 500 metres. A speed session must always start with a warm up jog of around 8 to 10 minutes. This may consist of 3 to 4 loops, or you could jog from home to wherever you intend to carry out your intervals session. After the warm-up you may wish to do some easy stretching, although I'm not at all keen on this (see How to run a marathon - 7 - speedwork).

At the final few metres of the warm up, take a couple of deep breaths and proceed to run two laps - fast. Not as fast as you possibly can, since you need to repeat this effort several times, but reasonably fast. Imagine you're trying to catch up with someone who is also running. Look at your stopwatch as you complete the first lap - you should complete the second lap at very close to the same time. As you approach the end of the second lap you'll be quite breathless, and your pulse will have rocketed. That's quite normal, and it's the whole point of this type of training. It will enable you to get used to running fast.

After two laps, slow down to a jog. It's better to jog than to give in to the temptation of stopping completely. During this jog, for one lap, you will recover your breath, and at the end of the lap you'll be ready for a second strong effort. Now you should aim to keep the same time for each lap as in your first effort. After two fast laps, you slow down to a jog once again. The pattern, therefore, is this:

4 laps jog - 2 fast/1 jog - 2 fast/1 jog - ... after your 5th or 6th (final) fast effort, the jog recovery should be extended to a total of 4 laps, i.e. about 10 minutes of cooling down. Six fast efforts will result in a total of 25 laps, i.e. 10km (assuming 400 metre laps at a running track). For a non-standard distance loop, which is incidently what I use nowadays, I keep repeating my fast efforts until at least 45 minutes after the start of the training session have elapsed. I then commence 8 minutes of cool down and head straight for a warm shower (it's very cold time at this time of the year...).

There are of course variations to the pattern outlined above. For instance, my very first interval sessions used to consist of four efforts of four laps each, with a one-lap walk in between each effort. But eventually I settled for the more straightforward 2 lap repeats, with a one lap jog in between.

This is a tiring session, but it's very good training for improving speed and the capacity to vary speed as necessary, especially in races and for going uphill. It should be preceded and followed by a day of rest or relatively easy training, i.e. the standard 10k run at an easy pace. To avoid the risk of overtraining or even injury, I think it's best to limit this type of session to one per week.

We will now introduce this session in Week 10 of our beginner's schedule for running a marathon. Here it is:

Week 10 (Monday to Sunday)
rest - 10k easy - 10k intervals - rest - 10k easy - rest - 75 minutes easy

Enjoy your running!