Interval training in running: guide and typical sessions

Interval training means alternating fast-paced segments with recovery segments. It's the most effective tool to improve speed and endurance — as long as you dose it properly.

What is interval training for?

Running at the same easy pace all the time improves endurance, but plateaus quickly. Interval training, on the other hand, develops your VO2max (your engine), your threshold (the pace you can sustain 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 400m repetitions at a brisk pace. Build 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 for 10km or a half marathon. Find your zones.
• Hill repeats: 8-10 × 30-45 s uphill. Builds strength without too much trauma, ideal at the start of prep.

What pace for interval work?

Not too fast, not too slow. On 30/30 or 400m repeats, aim for a "hard but repeatable" pace: the last repetition should feel like the first. If you blow up halfway through the session, you started too fast. Recovery should be really slow (jog or walk) so you can kick off again. These paces are calibrated to 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: progress happens when you recover between sessions. Doing too much = stagnation and injury risk. That's the whole point of 80/20.

Proper warm-up (non-negotiable)

20 minutes of very easy jogging + a few progressive accelerations before the session. Cold intervals lead to injury.

Interval workouts tailored to YOUR paces

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