When is it an Interval?



IV blog EN2PEAK offers you a unique tool to auto detect your interval efforts and if they fit the designated criteria, will highlight and classify them as intervals.

You might experience instances when you feel that you have put in a big effort during your workout, but 2PEAK does not recognize it by showing you an interval for it. Possibly there is a valid reason not to count it and here we explain you the logic we use and how you can affect your result by improving your performance (ideally!) or by adding tolerances so that 2PEAK “softens” its judgement.

  • first of all and interval is only considered an interval when there is at least two of the same or similar with the appropriate recovery in between them (hence the name). 2PEAK is already making the first exception here in that it “counts” also “single intervals” as long as they comply with the other rules here below.
  • minimum effort: you need to perform your interval consistently above your training zone limit (make sure your training zones are defined properly and that you update them regularly as your form improves using the test we describe here). We built in a tolerance of approx. 5% depending on the zone, which allows for small dips. Please be aware that Efforts in Z5 cannot be accurately monitored using heart rate and sprints (unter 10 seconds) are hard to get detected for runners using pace/speed. Power instead, always works. If you know you have performed your Z5 IVs correctly, but the intensity  could not be detected, add them manually in your log. More about monitoring Z5 intervals can be found here.
  • minimum duration: in order to count, an interval has to last a certain time (the minimum time needed to stimulate the intended energy source) which differs from zone to zone from a minimum of 6 seconds for Z5_high (sprints) to a minimum of 6 minutes for Z3
  • minimum consistency: you can potentially attain your requested minimum of say 300Watts by spending an alternating 10 seconds putting out 150W with the next 10 seconds putting out 450W and while that is certainly a hard effort as well, it will not stimulate the same energy source as spending time producing exactly 300W for an extended time. An effort that is too spread will fall outside the tolerance.
  • maximum outlier: you might lean into a corner and take force away from your pedal for a second or two, or your GPS signals drops for a few seconds while you are still running at your consistent pace. For such instances we allow for outliers lasting a few seconds to not impact the validity of your interval. But if the “break” lasts too long to be considered an outlier, the interval gets interrupted and possibly declared invalid.

In summary producing a consistent effort over a given time, recover from it and repeat the same way again, is what is required. Spreading intensities instead over time is an effort as well,  it is also tiresome but does not achieve the same goal, which is why we don’t count it in our interval detection tool.

The rules we apply are rather strict, we are aware of it, but they ultimately make an important contribution helping our athletes train at a high level of quality.

Performing “clean” intervals is not very easy, especially if you are just starting to train with structure. It is why we added a filter that allows you to increase the tolerances if you choose so and therefore allows you to find “more” intervals or better, to find your intervals more likely. Please note that increasing the tolerance does NOT move your training zone limits down, which means, that while the tolerance affects, minimum duration, minimum consistency and maximum outlier, no matter how much you increase it, if the minimum average effort required (average heart rate, average speed/pace or average power) is not reached, it will not be counted.


train safe!