Fast Talk Episode 168: How Much High Intensity Training Do We Need?

Podcasts Fast Talk
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Steady-state intervals are totally executable on the flatlands, unless you run out of gear, however, I do find that intervals, where you would surge for a short amount of time followed by settling back in at a lower wattage (say threshold), are really hard because there’s not enough resistance working against you to make the “lows” steady, rather you coast till you slow down to a speed where your gearing can catch up, and then come back on the power. If that makes sense.

What happens is that you go from 300w, to 450w, down to 200w, then back up to 300w. It’s really difficult to smoothly transition from 450w to 300w. Whereas on a climb that is easy peasy because the gradient is always applying resistance.

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Hi @smashsquatch,

That’s actually a question I’ve been meaning to ask Sebastian. I know he agrees that at a point VO2max is no longer trainable. But in his software he talks about the balance between VO2max and VLamax. I think some of what he’s talking about is the ability to use our full potential of either asset. But I also believe that he’s using a slightly different interpretation of VO2max than what most people think of. Really want to ask him about that…

To answer your questions, yes, at least in the cycling world, to hit our peak peak potential, volume is critical. If you want to be a Tour rider, there’s no way around training 25-30 hour weeks unfortunately.

Much of our conversation around optimizing training is addressing non-pros who have limited time and need to be the best they can on 6-12 hours per week. If they had unlimited time, I’d definitely have them do a lot more volume.

Likewise, to your second question, I don’t fully disagree. I really don’t hit athletes with true high very high intensity work such as Tabata’s until very close to racing to get those chemical adaptations.

But I do give HIT work throughout the year. During the base season, I prefer to give my athletes threshold work such as 5x5s and 4x8s. They do seem to aid structural changes more than to force a biochemical response. I don’t have definitive proof of that, but the fact that it takes between 10-14 weeks to see the full gains tells me that the benefits are more than biochemical.

Sorry to be slow on my response. Hope that helps!

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5x5 or 4x8 @ threshold is a very very easy workout. 5x5 @ 115% or 4x8 @ 108% would be different beasts.

So I’m genuinely curious what exactly are you hoping for with these workouts? Just getting the body ready to do longer intervals @ threshold?

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@anthonylane, 4X8 @ 100% FTP is “very very” easy? I think the FTP you’re using is low if that is how it feels for you.

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a 4x8 properly executed is max effort over the duration of all intervals (e.g. finishing the last one at your limit). The intensity you’ll be exercising at is threshold, but not 100% threshold (more like ~110%). I believe this episode talked about how the system you’ll be targeting is a range

Trevor Connor 22:57
… You don’t ride at 100% of threshold and you’re heading one energy system, and then go to 101% of threshold, and all of a sudden, you’re hitting an entirely different energy system. It is a range, so I think 110% still fits within that range, you’re still basically hitting the same energy system, you just hit it a little bit harder…

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Thanks Trevor! It would be helpful if maybe we had a pathway on this. A guide of the different systems we’re trying to improve, and what exactly improving those offer… and if in doing so creates any kind of trade off? And more importantly how best to improve said systems with general timelines to improve and necessary upkeep?

For example the different systems I’ve heard mentioned:

  • Mitochondrial density (e.g. I think this is long term high volume)
  • Mitochondrial function (e.g. I think this is short term Hiit)
  • capillary density/function
  • VO2max - I know you. say you can’t improve it, but I think that’s only if you’re well trained and can’t give it more time. That’s why I wonder if doing 2x a days can be a way to find more time and drive this up further. E.g. I can doing a low z2 session while sitting in certain meetings.
  • Lactate clearance
  • Increasing / decreasing VLAmax
  • Improving fatmax
  • Improving carbmax (Is this possible?)

So far I’ve seen us talk about

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4x8 @ FTP (meaning 100% of FTP) is not and should not be a challenging workout if your FTP is within reason. Now, if @trevor is referring to 4x8 as in the Seiler-style workout then yes, that’s challenging.

And IMO, 110% vs 100% of FTP IS quite a bit different in terms of RPE, and cardiac response. One is quite a bit easier than the other.

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I just can’t see 100% of FTP in a longer interval ever described as very very easy if the FTP is accurate.

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Sorry, but 8-minutes isn’t a long interval, and if your FTP is set accurately (it can vary day to day, week to week) a session of 4x8 @ threshold is not difficult. It’s like 60TSS and an intensity factor of .80.

Again, I don’t know what @trevor exact prescription is because he sort of generalized, but I’m just responding to his comment below. Maybe he meant something like what Seiler talks about when he says “4x8” which is at your maxiumum sustainable, but repeatable power. If that’s the case, then those are difficult…that I’M NOT DEBATING.

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This was covered in the episode (I responded earlier about this). Don’t take it so literal as threshold = 100%. It’s a range. I did a 4x8 Wednesday at threshold (~110%)… And it was brutal.

Trevor Connor 22:57
… You don’t ride at 100% of threshold and you’re heading one energy system, and then go to 101% of threshold, and all of a sudden, you’re hitting an entirely different energy system. It is a range, so I think 110% still fits within that range, you’re still basically hitting the same energy system, you just hit it a little bit harder…

Definitely go back and listen to some related episodes (or the interval pathway) and you’ll hear that 4x5 and 4x8 tends to be in context with max sustainable for that duration.

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Got it, my misinterpretation then.

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@anthonylane great points. I think that many of these issues you are mentioning come from pedal stroke, I notice this in athletes who can do as you mention when working against resistance but not when having to generate it on flat ground.

The intervals are doable indoors on a roller or outside on a flat, but it would just be a different type of practice for you.

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Hi everyone, sorry to be slow to pipe in here. Interesting discussion and debate. The conversation is quite long, so I’ll try to address everything I was tagged on, but I apologize if I missed something. Hope this gives some answers:

Execution
I do differ from Dr Seiler just slightly on these. In his studies, he had athletes do them as hard as they could while keeping the power consistent across all intervals. Since I use these in the base season, I focus more on keeping them around MLSS. Again, as you pointed out above, it’s not a specific number (i.e. going from 100% to 101% isn’t going to make a difference.) So, I give my athletes a few criteria:

  • Power should be in a range that is sustainable from interval to interval
  • But I don’t just prescribe power - heart rate and RPE are just as important if not more important. I give my athletes an upper limit on their heart rate that’s 1 BPM above their threshold. They aren’t allowed to go above that. The right wattage is what gets them to that heart rate by the third and fourth interval without going over.
  • Following those rules, the power is going to vary from session to session. For example, one session you may do 290 watts, the next session, you may find you have to back down to 280 watts and then the next time you may feel great and do 300 watts.
  • While my prescription is different from Dr Seiler’s I do find the end result is very similar. Using my prescription, most athletes find they are going as hard as they can by the fourth interval and wouldn’t have been able to go much harder if they had set a goal of hitting the same wattage in all four intervals.

Here’s an example of a session I did this winter to show you what I mean:

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Notice the power is the same each session. Also notice that I don’t hit the upper limit on my heart rate (dotted red line) until the third and fourth intervals.

How Hard Should These Feel
This is a really important point that we’ve been trying to communicate on the show lately. The focus of our work should be on targeting energy systems. Using “I really suffered” as a gauge is often a bad gauge. To hit many of our energy systems effectively, intervals SHOULDN’T be as hard as possible.

In the case of these intervals, they should hurt and the final interval should be a bit of a struggle, but overall, you should get through them feeling like you could have gone harder. I found it interesting that you mentioned the workout is only about 60-70 TSS. Here’s my data for the workout above:

image

I did70 TSS not just for the intervals but the entire workout and I was very happy with that workout.

I’ll also mention that I did a combination of 5x5s and 4x8s from the start of December to mid-March this year. I was doing them twice per week and most of those workouts were in the 70-80 TSS range. My wattage for the intervals from early December to mid-March improved about 60 watts. So, I was quite happy with both the execution and the results.

Final note - I actually just recorded two videos this morning on how to execute both 5x5s and 4x8s. Those videos should be on the site in a week or two.

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Finally caught up on this thread and I gotta say…you people are beautiful. This was super informative, totally nuanced, and I loved every word of it! :nerd_face:

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Hello. Love the podcast and this is my first time on the forum.

A couple of basic questions:

  1. Dr Seiler says “2 weekly HIT sessions” per week is enough for most people. But what is his definition of a session? Most of my planned (trainer) workouts are 60 min in length and are 60-80 TSS. But are we talking about the same thing?

Is a session 60min or 90min or 120min??

It is one thing to do 3 x 12min (@91-102% of FTP). Which I can manage easily enough… But its another thing to do 5x12.

Jay Vine (Zwift Academy winner) recently spoke about doing 4 x (4 x 5min @ V02max power) efforts… Which with 20min between each set would end up being a 4hours in the saddle.

What do we mean by “session”?

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I would suggest that if your 4x8s at 100% FTP is hard, then your FTP is too high, perhaps way too high. If you’re defining FTP as 95% of a power you can do for 20 minutes, doing that reduced output for 8 minutes shouldn’t be hard at all, even repeated 4 times. Or, say you define your FTP based off an Hour effort, why would doing 8 minutes at a power you can sustain for an hour be hard?

I find that RPE for 4x8s is a great way to validate my FTP estimate, using the points above. I find that if I do 4x8s at ~105% of estimated FTP and they’re hard, but manageable, but at 110-115% they’re unbearable, then my estimate is probably pretty accurate.

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@josemd, really sorry I never replied to your question back in July. My alerts weren’t working for a few weeks.

To answer your question… sort of. If you just compare a 2 hour base miles ride to a 2 hour tempo ride in isolation, you will get slightly more gains in the tempo ride. But the tempo ride also hits more energy systems and produces a lot more stress that you have to recover from.

But what’s important is how the ride fits into a weekly or longer plan. What’s important is the other work you’re doing. If you’re getting a couple days of high quality intensity work with the easy base miles rides in-between, then yes, the gains will be the same.

In fact, I’ll make the argument that the gains can be better because my experience is that when people go too hard on their easy days, their intensity days are lower quality.

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@nettic good question.

The exact length of the session doesn’t matter that much, though I’ll share some thoughts on that in a minute.

What’s important is the time you spend “at intensity.” For work around threshold, Dr Seiler did address this in one of our episodes and I fully agree with him - you generally see amateur riders doing a total of 25-40 minutes at intensity total. Pros are higher but not much - in the 35 to 45 minute range.

My personal biggest workout is hill repeats where I’ll do 4-6 repeats of an eight minute climb at threshold intensity for a total of 48 minutes at intensity on the really big days (I only do the six repeat session a few times each year.)

When you get into harder work such as Tabata’s, time at intensity gets even smaller. For example, when I do Tabata’s I’ll do three sessions of 5-8 minutes. Depending on whether I’m doing 20-10s or 15-15s, that’s about 7.5 to 12 minutes TOTAL at intensity.

I know that sounds small and I’ve already seen feedback that some of our members feel that’s surprisingly small. But honestly, that’s what we’ve seen again and again in athlete’s training. The purpose of an interval session is not to destroy you. No one workout is going to produce an adaptation. So, the important thing is to look long term - how are you building your work over weeks. Each interval session is just a small part of that and should be manageable.

That’s also why I don’t personally get too concerned about TSS. If executed right, an interval session in the 60-80 TSS range can be very effective. One of the most powerful sessions I do to build a peak for key events is a sprint workout and it generates about 40 TSS. TSS is not the measure of an interval session.

In terms of how long the total ride should be when you’re doing interval work depends on the intensity. There is some evidence that work which targets anaerobic pathways and endurance work can cancel one another. So, very high intensity work such as sprints should be kept short. I tell my athletes no more than 1 hour door-to-door.

With very hard intervals such as anaerobic capacity and VO2max work, I generally have my athletes keep the rides shorter - under two hours. With threshold work, since it targets most aerobic pathways, the ride can be any length. I’d just do the threshold work while your legs are fresh.

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Thanks for your reply. I read some of Joe Friel’s thoughts on the matter as well which made sense to me. Zone 3 riding is fine in the winter when you may have more limited time to ride due to weather, etc and during training camps. The other time of focusing on sustained Zone 3 (Tempo/sweet spot/race pace) is within 3 months of racing (my races are all in this zone from 3–7 hours). If I’m doing a block focusing on max aerobic power, glycolytic power, or sprint power, I would definitely go completely polarized where the easy days would be completely below aerobic threshold so I’m ready to hit it hard on the hard days!

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Thanks for your reply