Interval training in running: guide and sample sessions

Updated on 2026-06-23

Interval training means alternating fast running portions with recovery portions. It's the most effective tool to improve speed and endurance — as long as you dose it correctly.

What is interval training for?

Running always at the same easy pace improves endurance, but plateaus quickly. Interval training, on the other hand, develops your VO2max (your engine), your threshold (the pace you can hold for a long time) and your running economy. Result: you run faster for the same effort.

The main types of sessions

VO2max (short and intense) : 30 s fast / 30 s slow (the famous "30/30"), or repetitions of 400 m at a brisk pace. Work on your engine. See how to improve your VO2max.
Threshold (longer, less intense) : 2 to 4 × 8-12 min at "comfortably hard" pace. Push back the pace you can hold over 10 km or a half marathon. Find your zones.
Hills : 8-10 × 30-45 s uphill. Strengthens without too much trauma, ideal at the start of training.

At what pace to run the intervals?

Not too fast, not too slow. On 30/30 or 400 m reps, aim for a "difficult but repeatable" pace: the last repetition should look like the first. If you explode halfway through the session, you started too fast. Recovery should be really slow (jog or walk) to be able to push again. These paces are calibrated based on your VMA.

How many times per week?

1 to 2 quality sessions per week maximum, the rest at easy endurance pace. Interval training is demanding: it's by recovering between sessions that you progress. Doing too much = stagnation and risk of injury. It's all about the balance of 80/20.

Warm up properly (non-negotiable)

20 minutes of very easy jogging + a few progressive accelerations before the session. Interval training hurts when done cold.

Interval training calibrated to YOUR paces

The right interval training depends on your actual level. Sports Coach AI calculates your target paces based on your recent performances and places quality sessions at the right time in your week, without overloading you.