What is the limiting factor for aerobic performance in trained athletes?

[Wayne666]

this just is not the case.. cellular metabalism of oxygen is not the limiter

That is my understanding as well, "instantaneous" increases in power are attainable by breathing hyperoxic air and thereby delivering oxygen to the muscle at a greater rate. If performance was limited by cellular metabolism of oxygen, the muscle wouldn't have the capacity to use the additional oxygen.

 

[doctorSpoc]

That is my understanding as well, "instantaneous" increases in power are attainable by breathing hyperoxic air and thereby delivering oxygen to the muscle at a greater rate. If performance was limited by cellular metabolism of oxygen, the muscle wouldn't have the capacity to use the additional oxygen.

exactly... and EPO and blood transfusions wouldn't be effective either since the cells wouldn't be able to utilize the extra oxygen provided by the greater density of red blood cells...but we know that EPO and blood transfusions are VERY effective.

basically it comes down to this... your muscles will use all the oxygen you can get to them. the largest factors.. heart and lung capacity is for the most part set by genetics... capillarization takes years and years to develop.

 

[Wayne666]

your muscles will use all the oxygen you can get to them. the largest factors.. heart and lung capacity is for the most part set by genetics... capillarization takes years and years to develop.

Although I believe "lung capacity" typically isn't considered much of a limiting factor either b/c they are more than adequate to fully oxygenate the blood passing thru them. My understanding is that only some highly trained athletes performing short, maximal efforts desaturate their blood.

 

[doctorSpoc]

Hello LAnierb,

1.Pretty much all are wrong when it comes to a competitive athlete.VO2max and aerobic metabolism are a very old concept and a myth. I have seen Pros with average VO2 (both absolute and relative) and being great riders on the road and even the lab and viceversa. Don´t worry, Vo2 max is not "the limiting factor".
2.Your muscles will extract all the O2 needed for the most part. O2 is almost entirely bond to hemoglobin (Hgb) 4 O2 per Hgb, and with the action of 2,3,DPG is released to the cell. However, not even under the most intensity exercise Hgb unloads the whole 4 O2´s adhered to it.
3. It is the efficiency of muscles to utilize fuel (CHO and FFA) and deal with glycolysis by-products (Lactate), acidosis, pi..etc..what really makes the difference.

It is not at the cardiorespiratory level, neither at the circulation level...it is at the cellular level and all that happens there what makes the different in this sport. You can have an amazing VO2max (I have seen many) and develope huge power (also seen many) but then at the cellular level, you are very poor adapted to use fuels efficientely and on the road you are just an average rider. Same can happen the other way around.

Hope it helps,

Cheers.

with all due respect... this shows ignorance of what VO2max represents... VO2max is not simply the amount of oxygen that can be enahaled or oxygenated or even simpley how much oxygen that can be delivered to the cell... VO2max is the amount of oxygen that is USED, per unit time, per kg of body weight... VO2max IS strickly THE representation of how much energy the athelete can produce aerobically taking everthing together (cardiac output, lung capacity, capillarization AND cell metabolism). VO2max doesn't take into consideration addaptations like cooling, pain management, productions of endorphens, mechanics of the athelete, motivation etc. taking that into consideration... i really can't make sense out of your post.

 

[frenchyge]

Consider that the poster posts infrequently, and only then to tell the rest of us that everything we know or do is wrong. Of course, through research and profound experience among the elite, he has evidence to prove all of this except that he can't show it to anyone yet because it hasn't been written down and published, nor peer reviewed.

Personally, I can't wait to see the results of Urkiola2's world-changing discovery, but until that person's willing to share some of his evidence then I'll just regard the posts as trolling.

 

[jsirabella]

Honestly the amazing part to me is how he gets under everyone's skin. I mean even me who has only been on these boards for several months have started to ignore his posts a month or so ago....

I will give the man credit for getting attention though....it does take a certain talent.

Just as an fyi, stop giving him attention and he will eventually give up and go away. But I guess if we can keep a 150 page thread going for inspiration (??), why not respond to him too. If you are not inspired by page 50 or so I would try some supps instead...lol....they work alot faster...

...lol

Also I really do not see the confusion about the seated and standing difference in watts...it would seem kind of natural that standing power output would be higher. I mean the fact that he can ride standed for over and hour is amazing to me but I do not see why this is strange.

-Js

Consider that the poster posts infrequently, and only then to tell the rest of us that everything we know or do is wrong. Of course, through research and profound experience among the elite, he has evidence to prove all of this except that he can't show it to anyone yet because it hasn't been written down and published, nor peer reviewed.

Personally, I can't wait to see the results of Urkiola2's world-changing discovery, but until that person's willing to share some of his evidence then I'll just regard the posts as trolling.

 

[acoggan]

Consider that the poster posts infrequently, and only then to tell the rest of us that everything we know or do is wrong. Of course, through research and profound experience among the elite, he has evidence to prove all of this except that he can't show it to anyone yet because it hasn't been written down and published, nor peer reviewed.

Personally, I can't wait to see the results of Urkiola2's world-changing discovery, but until that person's willing to share some of his evidence then I'll just regard the posts as trolling.

Having corresponded sporadically with Urkiola2 over the years, I think the issue here is simply one of communicating in a foreign language and via the web. I say that because he does, in fact, have significant experience with professional cyclists and a strong background in exercise physiology.* Knowing that, I read his most recent post not as a troll, but merely indicating that he believes that the primary limiting factor for aerobic performance in trained athletes (which is a slightly different question than the primary limiting factor for VO2max) would be muscle metabolism...and on that point he would be right.

*That is, if it is who I think it is...not that he's trying to hide his identify as far as I can tell, I'm just not 100% sure that I've guessed correctly.

 

[frenchyge]

Having corresponded sporadically with Urkiola2 over the years, I think the issue here is simply one of communicating in a foreign language and via the web.

That was my initial thought as well, which I believed to be supported by your failure to rebuff him, as you have others in the past.

Knowing that, I read his most recent post not as a troll, but merely indicating that he believes that the primary limiting factor for aerobic performance in trained athletes (which is a slightly different question than the primary limiting factor for VO2max) would be muscle metabolism...and on that point he would be right.

Agreed, so do you have any support for his statement that the concept of aerobic metabolism is a myth? I thought the metabolic chemical processes were pretty well established, and heavily driven by the abundance of oxygen available within the cell. Urkiola2 states that the muscles will extract all the oxygen needed, but I thought it was pretty widely believed within the physiology community that oxygen delivery to the working tissues was the limiting factor for sustainable energy production. As doctorSpoc points out, if you increase oxygen availability to the tissues, sustainable power output suddenly increases.

I don't disagree with the statement that...

3. It is the efficiency of muscles to utilize fuel (CHO and FFA) and deal with glycolysis by-products (Lactate), acidosis, pi..etc..what really makes the difference.

...but again, all that stuff seems to be driven by the availability of oxygen until the mythical concept of aerobic metabolism is de-bunked.

 

[ric_stern/RST]

*That is, if it is who I think it is...not that he's trying to hide his identify as far as I can tell, I'm just not 100% sure that I've guessed correctly.

I think it is who you think it is... i can tell this cause, i can read your mind Andy! ;-)

PM me if you want to see if your guess is the same as my guess.

ric

 

[RHR38]

Limiting factor depends where you're targeting for.

If your target is TT championship, then it's FTP for that duration. If your target is one day race championship, then it's medium high-high vo2max with super ability to go anaerobic-clear lactate mixed with team tactics.

For stage racer it's mostly FTP, if it's serious stage racing where team is build around captain(s).

 

[doctorSpoc]

Having corresponded sporadically with Urkiola2 over the years, I think the issue here is simply one of communicating in a foreign language and via the web. I say that because he does, in fact, have significant experience with professional cyclists and a strong background in exercise physiology.* Knowing that, I read his most recent post not as a troll, but merely indicating that he believes that the primary limiting factor for aerobic performance in trained athletes (which is a slightly different question than the primary limiting factor for VO2max) would be muscle metabolism...and on that point he would be right.

*That is, if it is who I think it is...not that he's trying to hide his identify as far as I can tell, I'm just not 100% sure that I've guessed correctly.

i'm still having all kinds of trouble making any kinds of sense out of what he actually wrote... but if when he says aerobic performance, he's refering to competition (i think VO2max could be looked at as aerobic performance as well) and more specifically mass start competition, then yes, things suddenly become much more complicated because in mass start racing and even in shorter TTs AnCap and NMP (not for the TT) can play a significant and even dominant roll in "performance" given a VO2max of a minimum level.

maybe we should clearify with the OP... when you say performance, do you mean in the pure sense of VO2max, or do you mean real world performance in competition? If you are refering to in competition performance then you really need to describe the type of competion, because different sorts of competition will require a different set of abilities.

 

[lanierb]

i'm still having all kinds of trouble making any kinds of sense out of what he actually wrote... but if when he says aerobic performance, he's refering to competition (i think VO2max could be looked at as aerobic performance as well) and more specifically mass start competition, then yes, things suddenly become much more complicated because in mass start racing and even in shorter TTs AnCap and NMP (not for the TT) can play a significant and even dominant roll in "performance" given a VO2max of a minimum level.

maybe we should clearify with the OP... when you say performance, do you mean in the pure sense of VO2max, or do you mean real world performance in competition? If you are refering to in competition performance then you really need to describe the type of competion, because different sorts of competition will require a different set of abilities.

My question was mostly about FTP because for most things that's a pretty good indicator of performance. I'm interested in all the discussion though. I'm still not convinced there's a consensus answer. (At least I'm confused.)

 

[rmur17]

My question was mostly about FTP because for most things that's a pretty good indicator of performance. I'm interested in all the discussion though. I'm still not convinced there's a consensus answer. (At least I'm confused.)

FTP = the product of:

1. Vo2max (liters of O2 consumed)
2. The percentage of Vo2max at one can sustain at threshold
3. Efficiency (W per liter of O2)

I realize there are myriad components that go into each leg of the triad. Too many for my formal training and brain to take though I'll admit I'd like to hear more from the boffins.

 

[Urkiola2]

Well, It looks that I am not wellcome in this forum….I just wanted to give some different points of view form a different perspectve. In my opinion that is what you do in a forum, which is an open place where people exchanges ideas, concepts, hypothesis…etc. However for some, it looks to me that this forum is pretty much unidirectional…



When I expose my ideas and talk about my background with elite cyclists is because since I don´t have studies published I have to back up my “concepts/ideas” at least somehow…and sincerely the only back-up I have is the empiric experiences with those elite athletes I work with. I have never had the chance to team up with a research group to publish data (and I have tons of it) since I work 60-80h/week and have been travelling 120+ days/year. However I promise I will be writing as soon as I can…



Thanks Andy for you words. Maybe I did not get my point across right.

Dr. Coggan is one of the best exercise physiologists in the world and this forum is extremely lucky to have such an eminence, so that many people in this forum could learn a lot from him.



With all due respect as well, Drspoc, you are wrong about the question adressed by Lanierb and maybe should have read it again or maybe you did but ignore some physiological and biochemical factors beyobd the heart, lungs and capillaries. The question is “What is the limiting factor for aerobic performance in trained athletes?” and NOT “What is the limiting factor for VO2 max?”. Of course it is very obvious the assumption you make about limiting factor of VO2 max and it is Physiology 101 since VO2 max = Q * a-v difference, whereQ (Cardiac Output) is: SV * HR * a-v difference, where SV is Stroke Volume, which according to Frank-Starling law is EDV (end diastolic volume)- ESV (end diastolic volume) and a-v diff. is the arteriovenous difference. a-v difference does not change much between trained and sedentary individuals. So it is pretty obvious DrSpoc, that Q (Cardiac Output) is the limiting factor for VO2 max. (BTW …do you know which is the limiting factor for Cardiac Output?…Just a clue…it is an anatomical tissue…

Anyways, when we talk about VO2 max we are making several assumptions that are not necessarely right but we make them by convenience: For example we have to assume that VO2 max measured in labs is done through an open circuit indirect calorimetry which estimates VO2 max. I won´t get into the whole metabolic measurements derived from VO2 and VCO2 which neglect Protein utilisation and therefore we use the term R or RER as an estimation of RQ (which again is an estimation since it is a non-protein RQ). We could be talking about this for a long time and will will be probably getting into diffeent matters. Just stress the point that VO2max is an indirect max measurement.



Other issues that can prove that VO2 max is not the limiting factor for performance (and have been studien on peer-reviewed journals) are:



- Elite athletes continue to improve their performances for many years afer reaching their VO2 max. So we must assume that there are other factors than VO2 max affecting performance. Also with altitide training and blood doping or EPO, performance increases last a few days whereas a higher VO2 max lasts longer.

- It has been proven that VO2 max and Cardiac Output increase more by running than by swimming. In the 70´s it was popular for swimmers to run in order to increase VO2 max and Cardiac Output. However, although they improved those parameters the transference to swimming did not occur since they did not improve their performance…which suggests that muscle metabolism was what really helped improved performance. This is another argument against beingO2 max limiting factor for performance.

- Fiber type and the respective oxidative enzimes can vary largely among subjets. O2 exchange is 3-5 times higher in Type I fibers than Type IIa or IIb (IIx). So muscle fiber type composition and its enzimes (something we forget to mention often) can vary largely among individuals and change the whole metabolic spectrum and therefore performance…and these are metabolic events occuring at the muscle level.

- It is obvious that VO2 max differs largely between heterogeneous subjects (e.g. elite vs recreational vs sedentary subjects). A Pro cyclists has a higher VO2 max than a recreational rider. That is very obvious. However VO2 max is pretty similar between homogeneous groups (e.g. Pro tour riders or world class marathon runners). It is even VERY similar between elite amateurs and world class cyclists- Therefore we would not need to organize any marathon or other endurance events since we could do them in the lab just by assesing VO2 max if this latter was the limiting factor for performance. However VO2 max is more of a “required”element for performance rather than a limiting factor.

- It has VERY well established, especially from the empirical point of view and worldwide by many exercise physiologists that when we estimate VO2 max among homogeneous groups of cyclists there is not a defenite correlation between VO2 max and performance during the competition, therefore VO2 max is consider from the practical point of view a poor predictor of performance. I have tested TdF, Giro , Vuelta , World Championships and classics winners who had lower VO2 max than others who do not succeed at the pro level or even don´t even make it to professionals. Anyone having access to a large pool of pro cyclists and elite amateurs can confirm this point. I can also confirm this point from my own experience. I raced at a pro level (a very low key pro level though, and I have to admit that I consider myself a frustrated professional). My relative VO2 max done in diferent labs was 74-76 ml·kg-1·min-1. I never made it to the top level of Profesionalism and was a pretty bad and average pro though and only lasted 2 years...….I have tested important pros with lower VO2 max than the one I used to have and they made it to the top teams and level and I did not. This also happens among elite runners where there is a large discrepancy between VO2 max and performance studied in labs worldwide included in mine.

- In the 1920´s Dr. A.V. Hill showed that O2 was the limiting factor for muscle contraction and that lactic acid (LA) was produced as a consequence of lack of O2 availability. He even won the Nobel price for this discovery. This idea was sustained for many years untill other researchers started to challenge this concept. In 1968 Jobsis y Stainsby and in 1986 Connett et al., found that Lactic acid was produced in muscle under fully aerobic conditions. So O2 availability was not a limiting factor for lactic acid production. This is now recognized by pretty much the entire scientific community. So here we star talking about cellular mechanisims. If LA is produced under fully aerobic conditions it means that glucolysis it is as well and glycolysis could be perfectly aerobic. So important cellular events occur in the presence of O2 and lactate oxidation (removal) from the muscle and specific enzime and its isoforms like LDH´s, mLDH and different isoforms of lactate transporters (MCT´s) have to be taking into account. This is a relative “new” and promissing field since there are still no studies related to the mentioned elements related to performance and needless to say about the differences between recreational vs elite cyclists…



Then we can talk, although I won´t because it would be much longer than what I am already writing (sorry for this long response) about the limiting factors for performance. Today the reality is that still we have not found a single limiting factor for performance!!. However, most scientist worldwide coincide that limiting factor for performance, as Dr. Coggan says as well, are related to muscle metabolism and all the events happening at the cellular level with a whole array of local factors in the cellular and extracellular “mielu”.



DrSpoc and Wynne666; about your statement about EPO, Hyperoxygen training and Blood doping, again you are making a very obvious assumption since none of this assumptions are physiological. So they don´t happen in the “real physiological world”. Blood oxygen-carrying capacity is 18-20 ml O2 ·ml-1. With EPO or blood doping as well as other 2,3 DPG modifiers, synthetic hemoglobins and Perfluorocarbons (PFC´s) the oxigen-carying capacity of blood can be increased to more than 30 ml O2 ·ml-1. However as I stated before none of this is physiological and it is beyond normal human physiology.





Frenchyge, since you think I am a troll, I will have to tell you that your comment was a bit unfortunate. I don´t need to prove that aerobic metabolism and/or VO2 max are not the limiting factors for performance and don´t need to give you “world-changing discovery´s results” since it has never been proven by modern physiology that aerobic metabolism is the limiting factor for performance in trained athletes and even more specific in elite cyclists. Others have proven that for me as I stated above that VO2 max and/or aerobic capacity are not the limiting factors for oerformance…. Maybe I should not used the word "Myth" when referring to VO2 max or aerobic capacity but the truth is that no-one has yet proved in modern physiology that either of these factors are the limiting ones for performance (at a competitive level). Maybe since it looks like you have lots of knowledge and experience in the matter, I now ask you to show me a single peer reviewed paper which states that determination of VO2 max will predict if you can win a Tour de France, a world championship or the 1-h record…..or that can even discriminate in bewteen a same group of elite cyclists or runners for example. So I don´t have to give you results for, what you mentioned, a“world-cycling discovery” since there is no need to because there is not such a need/case for that….



Anyways sorry for the long response, which will probably will be my last intervention in the forum. Due to the genesis of the word “forum” I thought I could show different ideas and/or concepts which I extract straight from pro cyclists and could create a discussion forum per se.



Cheers.

 

[Felt_Rider]

Anyways sorry for the long response, which will probably will be my last intervention in the forum.

No need to run away so quickly
Some of us lurkers like to see various commentary.

Due to the genesis of the word “forum” I thought I could show different ideas and/or concepts which I extract straight from pro cyclists and could create a discussion forum per se.

In the strength world there was the late Dr. Mel Siff (known as a guru in the strength world) that had a web page called "puzzles and paradoxes" that had different topics of discussion to get some of us fixated on certain ideas to consider a few things "outside of the box". I enjoyed him presenting different ideas of discussion.

 

[frenchyge]

Well, It looks that I am not wellcome in this forum….I just wanted to give some different points of view form a different perspectve. In my opinion that is what you do in a forum, which is an open place where people exchanges ideas, concepts, hypothesis…etc. However for some, it looks to me that this forum is pretty much unidirectional…

I can assure you that that is not the case, but you must understand that on an internet forum such as this it is not uncommon for people to anonymously spout off about stuff they know nothing about simply as a way to boost their own egos or arouse the ire of others. Unfortunate as that is, we all must back up our statements in some way if we expect them to be taken seriously by others -- especially if those statements are broad criticisms (such as your FTP comments in the other thread), or sweeping statements that other posters are wrong. Failure to provide some factual backup or explanation puts one at risk of having their posts dismissed -- which would be unfortunate in the case of one with your experience and knowledge.

While I doubt there are more than 1 or 2 posters here that can come close to matching your experience in the field, there are plenty that have absorbed enough information to be able to have reasonable discussions of the topics at hand. In my opinion, you are as welcome here as any poster who shares information or insight which helps improve the overall knowledge of the group. In that light, thank you for your detailed explanation which I can only someday hope to understand.

Frenchyge...<snip>....

Maybe since it looks like you have lots of knowledge and experience in the matter, I now ask you to show me a single peer reviewed paper which states that determination of VO2 max will predict if you can win a Tour de France, a world championship or the 1-h record…..or that can even discriminate in bewteen a same group of elite cyclists or runners for example.

Some knowledge, and very little experience. I would agree that it would be impossible to pick the TdF champion from a listing of VO2max results, so I would not be able to respond to that challenge. However, I don't think that really relates to the original poster's question, as he wasn't asking about a limiting factor among a group of individuals, but rather the limiting factor within himself as an individual. IOW, since his power capability seems to be higher while standing than sitting, what limiting factor must the change in position be removing from his riding. Even if VO2max sets the upper limit for an individual's potential aerobic output (ie, it is a limit for an individual's lab test performance), that doesn't mean that it's the most important factor for actual raceday results, as your experience and data seems to indicate.

As for the original poster, I don't really have a good explanation for why his standing performance would be better than sitting. Engaging greater muscle mass may help reduce a capillarization bottleneck around certain tissues, but I would expect the cost of engaging unrelated muscles would be greater than the benefits that it would provide. Urkiola2, any thoughts on why the OP would be able to produce greater 1hr power while standing as opposed to seated? Have you worked with any elite riders who showed a similar tendency?

 

[Ade Merckx]

Aww man! is that it? This has the potential to be the most informative thread since well...the last really informative thread. Is the U2 man coming back? Have the 'haters' had their day? Will someone else re define VO2max for the nth time? what about psychology could that be a limiting factor? common guys keep it going

 

[ric_stern/RST]

Urkiola2 we hope you stay on the forum, there's good info from yourself and Andy C (and others).

ric

 

[QikSmurf]

Clearly there is more than one point of view here and no one has been able to give the OP a definitive answer. I think that there is evidence to suggest that VO2max and all related cardiac functions are relevant, but not necessarily THE, limiting factors.

I have seen many cases where athletes have an exceptional one-off performance that they never repeat again. What makes an Olympic athlete perform a Personal Best result in a single event, and then never be able to repeat that feat again? This has happened countless times in sporting events around the world.

In reality, the limiting factor for Aerobic Performance is your Genetic make-up. You can improve your cardiac output significantly with the correct training, but you will always reach your pre-determined genetic limit after a while.

If you lined up 100 athletes in a race and tried to predict the order in which they would finish, physiological data would be but one half of the puzzle. People have tended to focus on the science of physiology when posting replies. I suggest that their psychological approach is as important as their physical preparation.

Quick anecdote to ponder: A psychiatric patient of my wife (patient A) has delusions of grandeur. Basically, he thinks he is Superman. In a recent fit of rage (when another patient (B) accused him of being puny), patient A lifted patient B above his shoulders and carried him down 2 flights of stairs before being overpowerd by guards. The amazing thing is that patient B weighs about 120kg and patient A is about 65kg wringing wet. The Hospital in question adjoins a golf course. Our Superman friend often runs onto the course and picks up golf balls and throws them back at the golfers. The tee is about a 1-wood distance from where he starts to throw the ball back at the golfers. In a fit of rage, patient A can throw a golf ball almost all the way back to the tee.

The point is that there is a lot more to human potential than laboratory numbers like Vo2max ;-)

Don't underestimate the power of the psyche!

 

[lanierb]

Well, It looks that I am not wellcome in this forum….

Thanks for a great post! You are most definitely welcome! It's clear I was vastly oversimplifiying things in my original post and that there really are a lot of things that factor into performance besides V02 Max. I guess my next question would be about how trainable these things are.