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Training & advice

Repetition or interval training

So, you want to run faster? There are many ways of training to make this happen. Running quickly over a set distance several times over is called repetition training and will improve your speed-endurance so that you can improve your times in endurance events. The recovery you have in between each repetition is crucial: the more recovery you have, the faster you will be able to run the repetitions so your speed will improve, if the recovery is kept short you may not achieve the same speed but you may be able to do more of them so your speed-endurance will improve. The recovery in between the repetitions is called the 'interval'. Whether you call it 'repetition training' or 'interval training' may depend on whether you are focused on the efforts or the recoveries but, in essence, they refer to the same session.

 So no matter what you call it, this sort of training will help you improve your times over set distances, so if, for example, you want to run your 10k faster than you have been doing you need to introduce reps or intervals. You can only improve a certain amount and will 'plateau' quickly if you only do 'steady' running or if you try to run a bit quicker each time you go out. It's time to get serious about speed to make those times come tumbling down!

Your reps need to be run at speeds that are faster than race pace. You will run them over a short(ish) distance, have a rest (interval) and then go again. You will do this several times over. By getting your body used to running at this faster pace, your race pace will feel easy when the gun goes off and so you will be able to increase the pace as the race goes on or even start more quickly.

How long or short should these reps be? This really depends specifically on what you are trying to improve. Do you feel that you lack a change of pace within the race, find it hard to go off quickly or find it hard to 'kick' to the finish? If so, you may want to do some short, sharp repetitions to improve leg speed and pure speed. These could be anything from 80 - 300 metre sprints.  However, if you feel that you get slower as the race goes on and can't maintain your early pace it may be that you need to do longer reps and these could be anything up to 3k (or two miles).  For a really good balance you could consider putting in two rep sessions per week, one with short, sharp reps and one with longer reps. For example a runner training for 10k may do 4 or 5 X 1 mile reps with 4 minutes recovery in between each one on a Tuesday night and 12 X 400m reps with 2 or 3 minutes recovery between each one on a Thursday night.

How long or short should the intervals be? This depends what you are trying to do. If you are trying to improve your cadence or leg speed you may need to have a longer recovery so you can run each repetition hard. The longer recovery will be at least the same time as it took you to run the effort. If you are trying to increase your speed-endurance so that you don't fade towards the end of the race you could keep the recoveries short, perhaps only half of the time that it took to run the effort, so that you learn to run hard whilst tired.

The amount of recovery could depend on the weather and the time of year. Generally runners will concentrate on improving their speed-endurance during the winter months, when they don't want to be hanging around and getting cold during long intervals, and move to improving speed during the summer when they don't have to wear as much gear, and so can move more quickly, and can take long recoveries without getting cold.

You may want to use your heart rate to monitor your recoveries. If you are looking to improve speed your heart rate could drop to as much as 60% of your maximum heart rate before going again but if speed-endurance is your aim you could go again when it is below 75% or so.

You need to consider the surface that you will run your repetitions on. You could use a running track and so measure the distance accurately but you don't have to use a track or measure accurately, for that matter. If you have a field or park that you can use regularly and you know that it is approximately half a mile around it, you could use this. You will get to know what time you run each lap in and so can monitor your individual progress without knowing the exact distance. You should consider running your repetitions on the surface you hope to race on so for many this could be the road. Think carefully about your venue though. Carry out your own risk assessment. If there are uneven surfaces or dark sections you may want to look elsewhere. Don't forget that you will be running faster than race pace and so don't want to be concerned about putting your foot into a pothole. Industrial estates in the evening can be good for these sorts of sessions as there should be next to no traffic and 3-2-1 courses are perfect.

This session will be more intense and a lot harder than your steady running. You should feel pleasantly tired afterwards and you should always try to replenish with food and liquids afterwards. Chocolate milk has just the right balance of protein and carbohydrate so you should consider taking one with you and drinking it as soon as you can after finishing. You should also ensure that you warm up before and cool down afterwards and then take an easy day the following day.

Some examples of repetition sessions you may do, to improve speed-endurance in the winter and speed in the summer are below. Notice how the number of repetitions and the length of the interval changes.


16 X 1 minute fast, 1 minute very slow

8 X 3 minutes fast, 3 minutes very slow

3 X 6 minutes fast, 4 minutes very slow


10 X 1 minute very  fast, 3 minutes very slow

5 X 3 minutes very fast, 5 minutes very slow

3 X 4 minutes very fast, 6 minutes very slow