How to best solve the programming puzzle

Hi everyone

After a decent build with volume and some LT2 sessions over the last 2 months, I will start a short block of higher intensity training next week.
I think I’m fairly well-developed peripherally but have some central limitations (if they were “separable”, but you get my point).

The week structure will look the following:
2 weeks “on”, 1 week “off”, 2 weeks “on”, 1 week “off”
Where in the “on” weeks I will perform two HIIT runs (short intervals) and one HIIT bike and in the “off” week I will not do any HIIT but probably focus more on motor control, maybe have one LT2 session in bike/run each.

My bike sessions will be “classic” HIIT, building the interval time from 2mins to 4mins over the four “on” weeks.
My run sessions will be short uphill intervals building from 60sec to 2:30min.

I know there is no “right” way to skin this cat but I still would like to ask a few questions (I don’t want to blow it up here, so I’m not going into detail about all variables and only pick a few :joy:):

  • In your opinion, does it make sense to build interval length over the weeks, e.g. from 2min to 4 min on the bike over the course of the four “on” weeks? Or would you start with 4min from the start as according to the Thibaut graph it gives the biggest bang for buck regarding T@VO2max and T@Qcmax? Or is it a “risk” that I might not be able to reach VO2max if I haven’t done these kind of intervals for a long time and therefore rather start with 2min?
  • How would you change interval duration and intensity for a more slow, enduring (diesel) type athlete opposed to a more explosive athlete? Would you prescribe shorter intervals for slow/enduring athletes to improve their MMP/MAP and longer intervals (4-6min e.g.) for more explosive athletes (to increase aerobic power and have less glycolytic action)? Just trying to understand more here, but I would consider myself a more slow, diesel-type athlete although that might have something to do with how I trained over the years.
  • In order to have the highest time@VO2max, what would be a good warm up? I thought I would do a progressive (build) warm up with a few strides/accelerations. e.g., 6min easy, 6min LT1, 3min LT2, 3min easy, 6x 30/30, 2min easy (that would be ~26min).
  • A less HIIT related question, but what would be an ideal gradient for the uphill intervals on the run (I would prefer to do them outside to not lose that “push off")?


  • After this block I plan to go back to more LT2 sessions but would maybe include some maintenance sessions (similar to strength training during a competition period). Have you experimented with that and where it fits in best (e.g., how much T@VO2max is needed for maintenance but also where it is best placed e.g., how many days before or after an LT2 session)?

Many thanks,


Hi @Sophie ,

Thanks so much for posting. For context and for others reading, I know you’re a well trained triathlete and as you say, likely a ‘diesel engine’ type athlete. Also as you note and WRT your question, there’s no right or wrong way to do things and always more than one way to skin the cat. Your method here seems totally logical.

As per Athletica we typically prescribe 2 or 3 build weeks and 1 recovery week so that totally aligns with my thinking and what can work well to build potential whilst keeping healthy.

These are classic ‘long intervals’ and highly suit the diesel engine phenotype.

As you allude to, there’s no right or wrong way here. My personal preference for any build is to start with a given distance or duration for your repetition (2,3,or 4 min) and build repetition number. - maybe 1 extra per week. T@VO2 will be similar between assuming you’re sticking with 2 min walk/jog recoveries. As always, stop at the point where you feel you could still do one or two more (whatever duration you choose).

Diesel as above. I’d keep the intensity around 95%v/pVO2max. For twitchy athletes, go short to get more bang for buck. The short effort and short recovery seems to control the stress response better, as lactate doesn’t get away from you as bad.

Anything in the heavy domain as you describe will do the job as Filip highlights here.

Research suggests anything from 4 to 18% is effective. Splitting hairs.

Yes - this is wise and why all Athletica sessions have a short bit of HIIT in them in both recovery microcycles and during the off-season training. Research suggests you’re better off if you just touch the signal quietly and walk away - you wind up being better off in the next block.


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I’d put myself in that category. No explosive power, but I can keep going for hours and hours without fatiguing. I found the 5 minute VO2 long HIIT VO2 max intervals under Workout Wizard diversity tab last year.

I just switched from 30 / 30s short HIIT on the turbo to the long HIIT on a nearby hill. The hill averages 6.2% with no super steep bits, it’s fairly steady. The hill takes between 3.5 mins to 4.5 mins depending on how high in the proscribed power range I’m working. Initially I started at the low end of the range, and now I use the first interval to calibrate my effort based on how it went.

If I find I’m like a fish breathing out of water, but can keep the effort going to the top, on the final section of the hill, then to me that feels about right. My max heart rate ends up about 93-95% of max, for each ascent.

At the top I turn round, stop to drink some water and have a snack if necessary. Then roll back down the hill to repeat.

I found I’ve been able to get consistent with each repeat, even down to the second some weeks.

Hope this helps.

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To me that’s best practice. You know the hill, you know the various markers on it and where you should be in time, and now, with live Workout Reserve available soon we have a number of tools at our disposal to gauge progress in key sets.

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Thanks to both of you for sharing your views, expertise and experience. I might report back how it’s going :wink:

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Oh @Prof is the one with expertise. I just just have a few months experience of executing long HIIT. I certainly seem to handle them well and recover as a slow twitcher. I’m quite able to do my workouts the day after…

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@Sophie thank you for these questions, we took ‘em and ran with them on our latest episode ; ‎The Athlete's Compass: Unlocking HIIT: Part 3 – Advanced Strategies and Listener Q&A on Apple Podcasts
Let me know if you have other questions…


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