Minimal effective dose vs. VO2 intervals--going too deep?

From the podcast episodes I have listened to, the topic of minimal effective dose comes up from time to time and my understanding is that if I am targeting zone 2 for example that I might benefit recovery wise from sticking to the lower end up zone 2 versus always pushing up to the top end and maybe getting extra fatigue for not much gain.

I can see how this applies to zone 2, sweet spot, threshold etc but it’s less clear when it comes to workouts above threshold. Especially when many trainers on the podcast also talk about dreading tough workouts or pushing really hard in certain training situations.

As an example, I completed ‘Luftee’ workout which was basically 4x4 with 3 minutes in between and after feeling pretty good after the first one I pushed it up to 350 watts from 340 and did that for 2 more before pushing it up to 360 for the last one which was definitely just about the most I could possibly do for that interval.

After the last one I was definitely well out of breath and the last 30 seconds felt like an eternity haha. Is pushing just a bit harder counter productive in this situation or do others also try to essentially max out when the workout calls for it?

“Make the hard days hard and the easy days easy”

as generalisations go, that one’s not bad

If you can complete the next scheduled workout well, then you didn’t go too hard.

1 Like

Hey @nate_merz

Good question!

When thinking about “minimal effective dose” this can relate to both intensity and volume.

Training in some zones might require more volume to be highly effective whereas others might take less overall time in zone to move the needle.

In the case of easy riding, I personally like to push to that upper end of zone 2 most of the time because I feel like it’s something I can manage week over week without issues. Of course, if I’m really fatigued from a big ride or event, a truly easy “recovery” ride is certainly in order. :sweat_smile:

When thinking about higher intensity zones though, such as VO2 Max, as you’ve mentioned, it’s really easy to take on a lot of stress in a short amount of time which could lead to the accumulation of a lot of fatigue, and create issues down the road if you’re doing too much.

In terms of those VO2 Max workouts, I’d say it’s usually fine to push yourself really hard (that’s the point in a way) but make sure that you’re not completely burying yourself to the point of not being able to complete your other scheduled workouts down the road. This could mean managing the effort by adjusting the length, or the overall number of intervals, as well as your average power.

Luftee is a great example because it’s relatively short, and has four really solid 4-minute long intervals which gets you a solid amount of time in zone. In your case, dialing in your power for each interval was a good idea as you should be working and breathing really hard during these. :muscle: :lungs: :anatomical_heart:

The concept of “minimal effective dose” is essentially being able to walk that line of doing just enough hard work when it’s needed to keep progressing (or at least not losing fitness depending on the individual’s goals). Often times more isn’t better, and we all have our limits to how much exercise stress we can handle each week, so finding that balance and getting those key workouts in when you can with quality is what’s important.

When you’re working above threshold, you should usually be going pretty close to max if you’re trying to push boundaries. Goes for VO2max, AC intervals, sprinting. If you’re training for an 8 minute climb or something like that that you need to do at just above threshold with gas in the tank, that’s different.

Training physiology/fitness - go HARD, manage the dose (e.g. total time in zone)

Training event specificity - go specific.

For clarity, I’m not saying you have to do 25 minutes as hard as you can for an effective VO2max workout. I AM saying intensity for the interval length you are working should be as maximal as you can repeat for the given total duration. Most AC and VO2max workouts, you want to be pushing right up to the border of not being able to meet the target by the end (or power is fading). IMO, you’re going to get more out of a workout of 6x1 min AC intervals that looks like 660, 650, 640, 620, 600, 595) than you are out of a 6x1min AC workout of 600W every time. This is the folly of doing VO2/AC and sprint work as a % of FTP.

MED is going to apply more to “should I do 16 minutes or 24 minutes today?” or “4 reps or 6 reps” when working above threshold.

Re your comment on zone 2 rides: there’s a time and place for everything. Yes, most people see zone 2 is 150-200W and do endurance rides at 199W like that’s going to make them better, and usually the fatigue becomes overwhelming if they’re riding enough volume. Most should aim middle or low-middle for the majority of their endurance riding. This is why some coaches really favor RPE for their more experienced athletes because then you get EASY rides on days where they don’t have their best form, and they might push high Z2 on the days where they’re feeling good.

Agnostic of a plan, it’s tough to give a recommendation that suits every endurance ride. I give my athletes both easy Z2 rides and some where they push higher. It depends. But the majority of their endurance riding is probably in that 60-65% of FTP range by prescription.


How do you feel about the papers on citrate synthase metabolism and activity and their implication for intensity on endurance days?

Do you feel that the benefit of working at high proportions of your ftp for endurance pace generally outweighs the risk that the nonlinear increases in fatigue impact your athletes ability to perform to the best of their ability on ‘hard’ days?

I don’t believe that in general, no. I think it depends entirely on the athlete and what they’re training for, where they are in their periodization, etc. I also think a lot of those types of studies end up splitting hairs with things that may be truly beneficial for Pog (e.g.) but have a lot less meaning and add unnecessary complexity to Joe Public’s training. Once you’re riding basically your physical limit of volume, then worry more about intensity of endurance riding. I would much rather someone ride 12 hours per week at 60% than 8 hours per week at 70%, and that is most of who I am dealing with. My highest volume guys are on about 16hrs per week because they have jobs, pets, partners, families, etc.