Currently I'm running 12 400m repeats on a track, with 3 minutes for each repeat: so roughly a minute and a half of recovery between each lap.

What constitutes 'good' quality for these intervals?

eg should I be aiming to hit exactly the same lap time throughout the session, or would that mean that I was going out too easy for the first few?

should I be doing less repeats? Increasing the recovery time between them?

(Currently I'm doing the first 4 in about 1:22, the next four at about 1:30, and the remainder fluctuating between 1:25 and 1:35)

1 Answer 1


Well that depends on what your goal is. Your intervals should be less than whatever your goal distance is - perhaps 50-75% of whatever the goal is.

You want the pace of the intervals to be consistent throughout the workout. The first ones will be easy but the last ones will be hard. As you get better, you want to reduce the rest time between intervals - or increase the number of intervals you do (not both at the same time).

Your goal is to run your goal distance at the pace of your intervals - so you want to start joining your intervals together to get there.

Alternatively, you can increase the pace of your interval.

  • What if I'm training for a marathon or further? I assume 50% of 42 kilometres would be rather too long for interval training, but I'd expect you'd get some benefit from speed work where you're going above goal pace.
    – JamesF
    Commented Feb 11, 2014 at 1:31
  • 1
    Marathon intervals are typically 1600m in length with a rest of up to 1600m. Put a 1-2km warmup in front and a 1-2km cooldown afterwards and build the total distance up to about 10-12km. You should also think about doing some tempo running. 8-10km at goal pace.
    – Sarge
    Commented Feb 11, 2014 at 17:01

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