Alternate above and below threshold to train your body's lactate clearance system
Over-under intervals are one of the most advanced and effective ways to improve performance near threshold.
These intervals alternate between:
Without full recovery.
They train your body to:
Over-under intervals teach your body to handle repeated changes in intensity around threshold. The harder "over" segments increase lactate production, while the slightly easier "under" segments force your body to keep working while clearing and reusing that lactate.
This creates a powerful training effect for athletes who need to stay strong even when effort changes frequently. It is especially useful for race preparation, threshold development, and advanced endurance work.
The key to over-under training is control. The "over" sections should be hard enough to challenge you, but not so hard that the session falls apart. The "under" sections are not recovery in the usual sense — they are still work, just slightly below threshold.
When done correctly, the session feels demanding from start to finish, but still structured and repeatable. Pacing matters a lot, because if the over sections are too aggressive, the whole workout quickly becomes unsustainable.
| Over-Under | Sweet Spot |
| High stress | Moderate stress |
| Advanced | Beginner-friendly |
| Lactate focus | Aerobic focus |
Let Endurly structure complex interval workouts for you
Get Started Free