That would make sense.
Ive only skim read the article and looked at the links to see what some of the claims are about.
I was coached by Tom for a while and generally he offers great advice backed up by research. Which is why I asked him to coach me.
Essentially, you’re right. But people here get really hooked on details. I happen to think the wrong details, but everyone has an opinion right?
Once you get over these and learn to love, or disregard, your FTP it all becomes much easier.
Do a few FTP tests, check out AI detection, walk away, relax.
It’s affected by vasodilatation which leads to lower oxygen perfusion to the contracting muscles. Vasodilation Is affected by skin temperature. Skin temperature is affected by ambient temperature, humidity and air flow…
FTP is affected by the conditions under which it is performed …
Good discussion, thanks.
Another spanner in the works is the correlation of power as in ftP and ‘physiologic/metabolic’ load.
Power (watts) is only a back calculation to whats going on in a physiologic/metabolic sense, now that is a whole new can of worms.
Similar but I’ve had a different story for 5+ years. Learn to feel the tipping point between stable and unstable physiology, call it FTP or CP or the border between heavy and severe intensity domains or go ISM style and call it the turbo zone.
Learn when to use FTP and when not to use it.
Relax.
Or is that your ability to express your FTP.
We’re saying the same thing but getting a different result.
Are you getting the same/optimal training stimulus because you’re training at your maximal steady state, if that output is at a lower Power output and a lower aerobic cost?
Agree. And that’s the part I can’t wrap my head around/decide where I sit.
If Power is a end result for the amount of Oxygen you can uptake on the bike, and you’re riding at “FTP” but it’s at a lower physiological cost. Does that equal the same stimulus?
Taken another way, away from riding Threshold intervals.
The year before last, and part of last year, I never rode with a fan on during any rides up to 90%FTP. My HR was sky high. I’m sure it did actually give me some really good adaptations that I’m currently missing, but, is it better for me to ride at 250W at 125bpm, or 220W at 130-140bpm? I
Maybe you were doing a form of heat training?
I think your question about adaptions being different or not based on conditions is very relevant. Semantic pedantry about FTP definition aside (I am guilty of this :-)) it begs the question; if output at physiological steady state is different under different conditions are adaptions then also different?
I suspect, it is also a question that is very difficult to answer. Given that there are many types of adaptions the answer is probably not either/or.
FTP is an outcome of the environmental conditions not something separate. There is no mythical value to be expressed, only the result under the conditions you conducted your test that day.
Tend to agree, the conditions and the day.
Pretty sure the adaptation should be the same if you are experiencing the same HR and level of fatigue yet outputting the less power, because your effort is the same it’s just the net result is less efficient.
Well, power is a measure of the output. Inputs are oxygen and glycogen. Stimulus is adaptations to the muscle fibres, primarily in the legs.
If you are outputting the same power, then all other things being equal, you are stimulating the same response. RPE could vary wildly, but the power output is measuring output from those muscles, and RPE doesn’t affect the stimulation itself.
I suppose it’s feasible that the physiological adaptations from that stimulation are impacted by environmental conditions too, but that would be nothing as compared to nutrition and rest.
I’m getting dragged in here, no matter how hard I try to stay out(!)
this is true but vo2 max (oxygen consumption) is not the same as power at ‘vo2max’. The athlete might still hit the same vo2 max numbers but at a lower power
Yes, but is it the same stimulus? As in, your muscles are producing less work, does that mean the stimulus is less?
Also, without a met cart, do we know that VO2 is actually achieved the exact same when you’re achieving less work? Is it just that more is lost to heat? Is that the same stimulus? Would it be possible to improve our cycling VO2max by sitting in a heat chamber that was hot enough to induce maximal breathing and HR?
I participated in a long term heat study while in university. Vo2 max wasnt the key factor (heat acclim was), but they did vo2max testing with us each time we came in as a benchmark. For example, we may be more or less fit each time we come in (absolute vo2max terms), but they would have us run at the same percent of vo2max each time (say, whatever pace acheives 60% vo2max). It was a running study, but the principles are the same for cycling.
They told me that vo2 max can remain the same but pace at vo2max can change substantially through improvements in running economy. I personally wasnt a runner at all, so my run pace wasnt super fast at vo2max, but my vo2 max was in the low 70s, which is very high. They told me if I did run training, then I would be able to substantially improve my pace at vo2max whether or not my actual vo2max changes in absolute terms. This implies pace at vo2max should also be hindered by environmental factors like excessive heat.
Vo2max would be achieved with less work (in terms of an ‘ftp’ at a lower wattage) because the body is less efficient due to the heat. Idk if its the ‘same stimulus’, id say its a lesser stimulus in absolute terms, but the same stimulus relatively speaking (more wattage and less heat = less wattage and more heat). You probably would be on deaths door if it was hot enough to induce vo2max while sitting, but its a scientific fact that you need to put out less watts to acheive vo2max in a relatively hotter environment. You can get acclimated to the heat and lessen the gap between a hot and temperate environment, but I dont believe you can be acclimated to the extent that it becomes irrelevant (but idk). This also implies that performance is negatively correlated with heat, holding all other factors constant. If I had to guess, I would say the hotter core (body) temperature is the leading explanation to why one has a lower ‘ftp’ indoors than outdoors, with the bike being stationary as opposed to rocking outside explaining most of the remaining difference.
I agree with all that you’ve said.
It doesn’t clarify for me whether the “lower stimulus” is a worthwhile sacrifice to make, or whether it leads to the same end result? Perhaps it’s better in the long run, using heat as the example, to train at a lower FTP without adequate cooling.
My hunch though, based on what we know about altitude and that the reduced output at altitude leads to less adaptations from exercise (at least at moderate-high intensity), is that we’re better off to do all that we can to ensure that output indoors matches that of outdoors.
The cost in terms of convenience, financial, noise, space, etc is not insignificant though.
FWIW…
Every rider I coach who trains a lot inside has a lower FTP indoors than outside, including me. The biggest differential I see is about 30W or 15% in one case. (I don’t care to argue about if its one FTP expressed differently or two FTPs… the point is, the threshold is FUNCTIONAL, so if you can’t FUNCTIONALLY put out the same power, it’s a different FTP.)
That said, I believe it’s possible to close that gap substantially through a number of means: cooling (fans!), bike fit (using the same fit on the trainer bike as on the outdoor bike), practice (mental and physical adaptations), and which resistance mode you use (yes, I believe this matters).
I generally test my athletes in the method that they train the most. I have quite a few power tests done on the trainer, and then I see race results or interval results when they get outside and they can do more. So to me, it makes sense to test where you’re going to train.
Anecdata: I did threshold testing outside in December and then did 2x20, 1x10 at 295W, but couldn’t hold 265W on the trainer as I had been off of interval work on the trainer for literally months. After about a month of playing around, I’m able to do 285W on the trainer again, so agree with Tom that the gap is possible to close to be quite small…
But you’re better off being able to feel things out and lead with RPE… and that’s hard to do without a lot of practice.
I’m also mad because Tom beat me to this… this was literally gonna be my next blog. Guess I’ll just send my athletes the link to this since it’s really good. Ha!
My guess…
2 riders, 1 does a majority of their training indoors. The other, outdoors, usually on steady gradients in mild temperatures. Essentially, what current research tells us is optimal.
The outdoor rider consistently puts out more power during work intervals. So, hypothetically, they improve more rapidly.
However, access to those steady climbs. Time taken to get to those climbs. Weather, time lost descending etc etc.
I suspect that if you’re indoor training environment is ideal. Cool, air conditioned with a minimum of 3 powerful fans, that one could get very close to optimal training based purely on convenience and time spent actually pedaling.
My takeaway. If you’re debating this here and don’t already have an optimal indoor training environment.
That should be ones main focus. If one chooses to train indoors.
Less typing, more earning, doing whatever it takes to have an optimal indoor training environment.
Large
Ventilated
Cooled
Many fans
One can never have too much fan 
What exactly are the ‘right fans’? In my earlier post, I mentioned that I use a few Lasko box fans. These are cheapo $20 fans from walmart. They are good, I guess? but not some industrial fan for $300 at costco. Can someone link me to a website or TR thread about what you guys all mean when you’re talking the ‘right’ fans? Thanks
Some obsolete models now, but a solid list to show the style discussed.