Under/Over Intervals - The Details

Under/over intervals are quite popular among cyclists—but what exactly are they, and what value do they offer for your performance?

What is the benefit of doing under/overs?

When you go above your threshold, your body produces a lot of metabolic waste products (e.g. hydrogen ions). When you return to riding below your threshold, your body works to clear this waste and shuttle lactate to be reused as energy. As you complete these intervals over time, you’ll notice that you recover more quickly after going above your threshold.

How far above and below my threshold should I go?

There is a grey zone roughly 5% above and below your threshold where your body transitions from heavy to severe exercise intensities. Therefore, you must make sure you go clearly above and below this grey zone. That’s why these intervals are often planned at around Zone 3 (for the “under”) and approximately 110% of FTP (Zone 5 for the “over”).

How should I move from Zone 3 to Zone 5?

When accelerating, alternate between seated and standing efforts. Seated accelerations place additional stress on the knees, which can be beneficial for strengthening these areas, but may also increase the risk of injury if too much stress is applied.

How long should each under and over section be?

It can take between 1–3 minutes for the body to fully adapt to the intensity of exercise. Therefore, if the intervals are shorter than 60 seconds, it’s possible you’re not getting the full benefit from the session. You would likely be riding in heart rate Zone 4 for much of the under/over intervals.

Are these better than normal threshold intervals?

Not necessarily. Under/over intervals stress your body in a different way and produce different adaptations. But this doesn’t mean they’re better or worse overall. For example, if you want to improve your ability to sustain threshold intensity for longer durations, both steady threshold intervals and under/over workouts can be helpful.

If you have any questions, please don’t hesitate to email me. 

Email: info@breakaway-coaching.com