How long can you keep improving without progressive increases in volume?

Essential question: How much is fitness development anchored to volume?

Over the last month or two I have been trialling Xert.

They have an interesting model that predicts increases in fitness over time. However, in my case, their AI simply refused to even put me on a “maintainance” plan unless I increased my bike volume from 6-7hrs a week to 10hrs. To improve meaningfully (e.g. put 5w on my 5min power in 6 months) it demanded a minimum of 15+ hours.

When I asked their authors, they said “the science says unless you progressively increase your workload you cannot get fitter, so our model assumes you need at least x hours for y w/kg”.

My perspective has always been that load was normalised to fitness, so if you could create novel stimulus by doing the same volume but at a higher workload this could be sufficient. However, I was firmly told “no, not possible, humans don’t work like that”.

But the volume the pros do remains largely similar year to year (even if it might be at a higher Kj load due to more power), so why must we steadily ramp our volume to infinity? Isn’t this a bit of a facile view on training?

To clarify - I’m talking here about volume, not load.


I wouldn’t put too much weight on that model, everyone responds to training differently and I don’t believe it can accurately predict how much volume you need to do to improve. That being said, you do need to progress to get faster, and you can do that by increasing intensity without increasing volume but only to a certain point where you won’t be sustainably recovering from your workouts anymore. The reason why the volume the pros do doesn’t increase year after year is because they are training at the limit of what they can actually recover from.


I think you know this, but no one can define this ceiling for you. When you hit that ceiling is hard to know. Alot is going to depend on your long term history with training as well as what you have been doing for the few months. I think you can continue to increase workload until you see yourself plateau.


I think this is dependent on you… That said, here is my personal longitudinal data starting at Training Age 1 (at fifty four):

Re: 2016 - I didn’t have a power meter long enough to trust the vo2max data.

dFRC is basically anaerobic capacity.

From an aerobic point-of-view, there are 3 basic aspects to fitness:

  • vo2max which is a key marker for cardio fitness and sets a ceiling on your ability to produce power aerobically
  • FTP or upper aerobic threshold which is the upper bound for producing power aerobically, and depending on your metabolic fitness, on the bike this is roughly your ability to produce sustained power for 30-70 minutes before fatiguing
  • lower aerobic threshold, which for lower volume athletes generally moves in conjunction with ftp, and is the boundary where you go from producing power mostly from the slow aerobic pathway (fat as fuel) to starting to use more carbohydrates as fuel.

As a rough first order approximation, I use total hours as a proxy for driving gains in the lower aerobic threshold.

Above FTP you need so much energy that you start “draining the anaerobic battery” (dFRC), heart rate rises towards max, and breathing rises towards max. For a strong surge, time to fail is a few minutes, but a well paced 20 minute test will burn through all your anaerobic battery.


the reality is, cycling is a sport where success is requires volume. Over the past year I’ve been at 14-16hrs/wk and even then there’s a limit on what I can achieve with the time I have available. There’s only so much work you can cram into a 7hr week and have it be productive. Increasing hours can give you more hours at lower intensity and help you grow in ways you just can’t with just doing hard workout after hard workout in a lower volume week.


I agree with their model in general, volume matters a lot and you’ll plateau fairly quick without it. You don’t need to increase to infinity, bc there are diminishing returns to volume just as there are with intensity. There is def a big genetic component that the model misses, by definition. These regression models are typically finding the best fit line through the data, so produce the average effect of some explanatory variable on the outcome variable, by definition. Genetics are captured by the ‘error term’. But to say that ftp increases with volume would hold empirically, for sure. If you’re lucky, you can high a high fitness on sub 10hours per week, but you’re not going ‘pro’ without 15-20+hours per week plus the right genetics. I’m sure most people couldn’t get 5w/kg even with 15-20hours per week bc genetics matter so much, tho they could have really great gains relative to their baseline. If you don’t have the genetics for it tho, you probably won’t have a high w/kg without the volume.

In my experience, I never have sustainably had volume beyond 8-9hours per week, but I have been fortunate to just have a disposition to be good at sports.

When I started cycling in my early 20s (fit from other non-endurance sports), I went from about 4w/kg to 5w/kg in 1-2 years at 75kg, then plateaued on ftp-type gains ever since, but continued to increase repeatability for the next 2 years. All at 8-9 hours per week structured, 2-3 ‘workout days’ while racing (which counted replaced workout days).

Took a few years off any structure and probably did 3-4 hours per week of not-necessarily-cycling aerobic exercise to be fit.

I got back into cycling 4 years ago and have averaged about 8 hours per week (as usual) the whole time. I started at around 4.5 w/kg- from previous fitness- and hover just below 5w/kg. I pretty much got my general aerobic fitness back in 3-4months. I have tailored some of my training blocks to hit power PRs in certain time durations. Ex, max 20min effort (5.4w/kg), 5min (6.4w/kg), 3min, 1min etc. I have produced big numbers which ftp estimators would suggest my ftp is way higher than I could actually hold. I’m just not a classic endurance sport body type and haven’t don’t the volume to develop like that.

All that to say, you might be lucky like me and be really strong compared to ‘normal’ riders on relatively low volume, but still won’t hang with the ‘big boys’ unless you get that volume in. And quite frankly, for a non elite athlete to train 8-9 hours per week regularly, that is quite something and consider a lot of volume to any normal person or even typical cyclist.

Think of the math too, 6 to 7 percent change is a lot bigger than 9 to 10. 6 is quite low volume too. You would prob want at least 4 days per week at 1.5hr+ as well as one of those at 2-3hr to ‘build the engine’. You’re not going to be super strong doing a 60min ride everyday, regardless of intensity. You need bigger stimulus to the body, in my opinion


If you assume the model is accurate, (that’s a big if) at best it’ll be describing typical response across a population. That’s how these sorts of models are trained. There’s a lot of individual variability that cannot be described by looking at population level trends.

Keep in mind the following truism for these sorts of things: All models are wrong. Some are useful.

I don’t disagree entirely with some of the response you got. The science “does” say you need progressive overload to increase fitness. The science however does not prescribe a specific amount of hours for X w/kg. There’s too much variability. What matters is if you can recover from the training and keep improving.

If their model says you need to increase volume to maintain, then the model is simply bad. That’s not maintenance anymore. If you’re doing 6 hours, you can do maintenance with a bit less than that.


It IS possible to increase fitness by increasing intensity within the hours you have, but that will top out fairly quickly when you just can’t handle any additional intensity. At that point you’re going to have to increase volume if you want to increase fitness. I would say that for me personally, it was far easier to increase fitness by adding hours and reducing intensity, but not everyone has the hours available to do that. Saying you can’t MAINTAIN your current fitness without increasing intensity and/or volume is just silly though.


I miss @TheCog


Fitness improvement ← progressive overload ← frequency x intensity x duration.

You can increase any lever or combination of them to create overload. Load must be recoverable, of course.


To quote someone famous


When it comes to endurance training, there are no adaptations induced by duration that aren’t induced by intensity. It’s only a matter of the total “dose”.

As to what “dose” is optimal, I don’t think science can really answer that question. As a half-century student of endurance sport, though, my impression is that things start to saturate somewhere around 15 h/wk.

IOW, if you’re only training 10 h/wk, then most individuals could probably get better by just training more. However, if you’re already doing 15 h/wk (on average, so 700-800 h/y), then I’m not so sure.”



Simply not true. Duration and intensity are not interchangeable. If your lens only gives you one dimension, the you’ll see everything as a total dose. But in reality, fitness is multi-dimensional. You can’t sprint your way into training for a marathon.

So if you decide that you’re limited in time and think that you can just do the same but add intensity, that will have limited gains since as your intensity increases, so does the focus of your training. In Xert terms, your focus duration decreases and your gains will start to move from your threshold, low intensity system towards your high and peak intensity systems. You’ll still make gains as that shifts. In fact, you can still improve your overall power profile and can continue to improve outcomes. But your endurance fitness will begin to be compromised on a relative basis if you simply opt to do more intensity instead of volume. Volume = Endurance. More volume = more endurance. That’s pretty fundamental. There are no short cuts other than putting in the training time.


I was quoting the “Cog”for “oldandfast” because he misses him


I know what he said, but the context was performance. My hunch in early 2020 was that for someone my age, desk jockey from 1986-2016, my heart needed low-intensity workouts to develop some more elastic, powerful and slow beats. And low-intensity work to combat on-the-job stress and make it easier for the body to adapt. I dunno about the rest of you but I’ve been in high-stress career roles since 1991, and consider it a big win that in 2020 I a) put my career on the back burner, and b) started focusing on heart health versus go-go-go interval performance. So far I feel that the metrics have proven my hunch was correct.


If we take W/kg as fitness metric, I have reached certain number twice:

  1. original TR HV plans, focused on intensity (~12h/week)
  2. my own base plans on loop, very low-intensity volume-centric approach (15-18h/week)

If I’d race and duration is up to 2h, there would be no difference. Yes, durability and TTE are way better with 2nd approach. But for specific goals, those additional benefits might not be important at all :man_shrugging:

I think he underestimates the cost, for me 3.5h with an IF of 0.81 is much less stressing than 20-30 minutes @ threshold. The former feels like a nice workout, the latter would wreck me. Even the anticipation of having to do long threshold intervals makes anxious. But doing 3.5-4h with an IF of around 0.8 excites me

1 Like

I think I’d like to stress the point I made at the end of the post once more: my position was not that you did not need novel stress to get fitter, but that you could increase the stress you put your body under by simply working at a higher output as you got fitter.

Imagine someone who does four 90 minutes z2 rides at 200w and one day of 30/15’s at 350w. Given six months of training, they might find themselves able to now do four 90 minutes rides at 220w, and the 30/15s at 375w. They are now putting their body under a (relatively) novel stimulus that should drive (some) adaptation.

They have not changed the intensity distribution, nor the volume. The load has remained the ‘same’ because the load is normalised to their capacity, but that doesn’t actually make 350w and 375w equivalent.

Obviously, at some point, this breaks down. But the argument I got into with Xert (and this is not to just bash them) was that they would say that the above person was unable to get faster.

yeah, but I’m coming around to wanting to ride hard on Wed night where its easier to summon the motivation to ride 20-40 minutes at threshold. And this week I’ve gone from 32-minutes @ 85% to 48 minutes without any issues. Another couple weeks pushing this thru the PMC progressive overload training optimization algorithm and my 85% power should be 90-ish minutes, making 20-40 minutes at threshold a straightforward proposition if my mental game is on.


Edited my post because I don’t want this thread to be about me; but the essence was that from my perspective I trained hard and focused on all of the supplemental factors for about five or six years on a similar volume and the only thing that has meaningfully changed is the watts.

So to the point:

Isn’t trainerroad as a piece of software based upon the idea that you can keep, to a certain extent, and for much longer than people give credit - keep getting faster without changing your volume? Fast athletes on ‘low volume’?

Sure you can, until you find your plateau. Everybody hits a plateau. You’ll hit it much faster on 3 hours per week. Unfortunately, we all ride next to genetic freaks that reach 4watt/kg on three hours per week and then easily hit 5watts/kg on 8.

I know an ex-pro who after sitting on his butt for 10 years and gaining 30 pounds at a desk job decided to race again. Within three or four months of training, he was going off the front of competitive masters 1-2-3 fields and then lapping them and he was still carrying an extra 20 pounds. The guy was a genetic misfit. And then he got bored of beating up on amateurs that never rode the Giro or the Olympics and went back into cycling retirement.

1 Like