What speed should I do my 400m intervals?

Running pace for 400m intervals (or 400m repeats) varies depending on the objective of the session and the recovery periods. Very often, 400m reps are run at 5k race pace with relatively short recoveries, but they can be run faster too.

Reps (repeats), Intervals, what’s the difference?

These two terms have become largely interchangeable, although actually they refer to different parts of a mixed pace training session. Reps, repeats or repetitions refer to the effort parts of the session, whereas interval is the part that follows the rep, i.e. the recovery.

So, a typical 400m interval session might be 10 x 400m @5k pace with 90-second recoveries.
The rep is the 400m part, the interval is the 90-second recovery.

However, it is common to call a 400m rep session a 400m interval session.

Example 1 – 400m at 1-mile race-pace

Here is a great two-in-one track session that is run faster than the typical 5k race pace.
It is quite a demanding session and is run at one-mile race pace*.

You can do this on your own or in the company of others. If you have an accurate GPS and some flat road you can also do it away from the track.

Why two-in-one?

Because you set your repetition time based on your performance during the first part of the session, and then you run the session accordingly. It’s very simple to remember, and you don’t need any fancy calculators or conversion sheets to work out your 400m rep times.

You can come to this session knowing very little about interval training and without any recent race results to base your pace on

Here’s what you do. After a good warm up for at least 10 minutes run some 50m strides to get yourself moving fluently; 4 or 5 gradually accelerating will be sufficient.
Then, run your fastest mile. If you are using a 400m track (most likely), there should be a curved line across the running track 9m before the finish line (1 mile = 1609m). Your mile run should be at a consistent pace over the four laps, and pretty much as fast as you can go. Record your time.

* In actual fact, this will likely be a little slower than your 1-mile race pace because it’s hard to replicate the motivation to run fast when running solo and not under race conditions. Nevertheless, it’s a good starting point and perfectly adequate in this application.

Now, divide your time by 4, e.g. if you ran 8 minutes for your mile, you get 2 mins —  a 6-minute mile would give you 1.30. This time is your rep time for your 400m session.

You can then run your 400m interval session at this pace, perhaps 8×400. This is fast running, so give yourself a decent recovery time between reps; a good starting point would be to jog very easily for 200m or up and down the straight for the same time as your rep time or even slightly longer (but keep it consistent).

As usual with this type of interval training, consistency is the key, your reps should all be run in the same time. If you cannot sustain a consistent pace, then allow yourself some extra recovery time (be prepared for some discomfort though).

For this session, the recovery time is less rigid and the emphasis is on recovering enough to ensure you can make a strong effort during the subsequent rep. Keep moving though, an easy jog or walk is ok.

This session will develop your running on various levels:

• It will help to improve your running form
• It will develop your ability to clear lactic acid from your muscles
• It will strengthen your mental toughness (this is a hard, fast pace and your 5k pace will seem considerably slower)

Keep a note of your times and how you performed, and use this session regularly to monitor and improve your fitness.