How To Use Interval Training Calculator (ITC)

29 March 2019by Robi Simonic

How To Use Interval Training Calculator (ITC)

29 March 2019by Robi Simonic
ITC: How to differentiate between same intervals but on different surfaces

We coaches test our athletes and on those values we’re planning their training scheme for a micro, macro or whatever cycle. We have one plan and we’re happy with it. We’re hoping that is enough!

My opinion from real world is that is not near enough.

I think this is utopic thinking of many S&C coaches, as there are many, many different “ways-to-go” of our sessions and then there are some natural consequences on which we don’t have any influence at all (sickness, injuries, travel, happy main coach who think that all intervals are the same.)  Being on “dark-side” of coaching for some time I can attest that we as S&C coaches have to be well prepared for different occasions on which we don’t have any influence as we often are.

That’s why I developed Interval Training Calculator excel spreadsheet to ease my job. To clarify what I am writing about I will write down short post.

Recently I tested myself on MAS 5 minute run. I performed these test on track and field surface. I inserted time and distance into ITC and excel spreadsheet manage to calculate MAS values for itself. Bravo Excel J. MAS being performance measure meaning maximal aerobic speed. Often explained as maximal speed with which we can run from 4,5 to 6,5 minutes.

Planned Interval training scheme on Track and field stadium

Then I planned first interval sessions for five weeks based on MAS running just on track and field surface. Running longer intervals on track, just in circles without shuttles, type 1 intervals based on Buchheit and Lauerson.

This is somehow ideal plan for me at this moment of being in very bad physical condition. That is why I planned longer intervals beginning at 90% and slowly progressing over 100% of tested MAS in 5 weeks.

This is ideal set up regarding always running on track and field stadium. But often I come to a track and field stadioum and find it closed for recreational use or I am in some other place and can’t go running on track.

Same is with athletes who are constantly in moving from a place to a different place and can’t always use same surface. That is why I also planned interval running performing intervals runs on a football field, on a grass. Which is quite different “feeling” on our body.  On a football field I can run in circles and watch the distance through GPS watch/app or I can do running with shuttles. As both (surface and shuttles) are more demanding I have “build-in” surface and shuttle losses in ITC, based on Mladen Jovanović and Dan Baker’s work.

So by calculating those losses in our plan, this plan is somehow getting closer to original one regarding energy expenditure and exertion level.

I (now) know that because of shuttles where we have to stop and accelerate this is harder on our body (Type 2 regarding on Buchheit and Lauerson work) but this are only 90 – 108% of MAS intensity intervals, so stoppages and accelerations aren’t of a maximal intensity and aren’t taking huge toll on our body.

Planned interval training scheme on football field

If you take a closer look in pics above, you can see that it takes lesser total interval distance when performed on grass, doing it with shuttles (because of build in calculation of surface and shuttle losses) from original straight runs. Total distance per 5-week cycle is more than 3% shorter on football field than on track. That means if you would run 100m on track you would do “only” 97m on football field. Which is not that much, but you have to look over-all picture of exertion during running on different surfaces with or w/o shuttles and longer distances than 100m.

Intensity is the same for whole cycle for both plans.

Some will argue that running on grass is more than 3% harder than run on track field (I already had one such, heated, conversation with fellow S&C coach). The 3% is regarded in distance not on intensity. So the reasoning behind this is little off for a fellow coach. We can’t mix/compare intensity of subjective measure of an effort with objective measure of distance/volume. I too believe that running on grass is harder than running on track and every individual has their own, different level of level of effort here. This is all approximation work and I believe it still better to have some options than none to build on.

Performing shuttles is also harder on body than straight forward run. Hence, intervals with shuttles are type 2 level of effort for Buchheit & Lauerson and straight forward running is type 1.

The idea behind this is that we have to have some substitutes for time when we couldn’t perform ideal trainings as we planned.

When we come to such an issue we better have already made plan at hand and not starting to think when it is already too late as our athletes are on the field.

The ITC spreadsheet has this “quick” built in option an you can calculate in matter of minutes “same-but-different” training protocols.

If you have any questions regarding purchasing ITC 1.2 spreadsheet, need more explanation regarding using it or have troubles with planning interval sessions for yourself or your athletes, you can contact me on email


I offer ITC 1.2 spreadsheet and workshops.


Robi Simonic