What is the limiting factor for aerobic performance in trained athletes? - Page 2

vetboy · #16 12-12.-2007

Quote:

Originally Posted by Wayne666

My understanding is that for most well-trained athletes for longer durations, the most probable limiting factor is the stroke-volume of the heart.

Forgive me if I misunderstand, but do you mean cardiac output? It's been a few years since my cardiac physiology courses, but it would seem to me that cardiac output, not stroke-volume, would be important for blood delivery to muscles. For example if my stroke-volume is lower than yours, but my heart beats faster than yours, I may have a higher cardiac output (ie volume of blood pumped per unit time).

Do I misunderstand?
Joe

doctorSpoc · #17 12-13.-2007

Quote:

Originally Posted by vetboy

Forgive me if I misunderstand, but do you mean cardiac output? It's been a few years since my cardiac physiology courses, but it would seem to me that cardiac output, not stroke-volume, would be important for blood delivery to muscles. For example if my stroke-volume is lower than yours, but my heart beats faster than yours, I may have a higher cardiac output (ie volume of blood pumped per unit time).

Do I misunderstand?
Joe

that sounds right to me... and from my reading potential for aerobic performance is limited by oxgen delivery to the muscles (cardiac output, capillarization etc), not the muscles utilization of the oxygen (mitochondria in muscles). VO2max would encompass both of those things so that really doesn't answer the OP's question.

to the OP... your #1 is the limiting factor... and so your potential is, for the most part set by your genetics.

Daniel Thomas · #18 12-13.-2007

Quote:

Originally Posted by Urkiola2

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.

So what are the consequences of this for training, Urkiola2? how can a rider ensure that they are well adapted at a cellular level?

doctorSpoc · #19 12-13.-2007

Quote:

Originally Posted by Daniel Thomas

So what are the consequences of this for training, Urkiola2? how can a rider ensure that they are well adapted at a cellular level?

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

Wayne666 · #20 12-13.-2007

Quote:

Originally Posted by vetboy

Forgive me if I misunderstand, but do you mean cardiac output? It's been a few years since my cardiac physiology courses, but it would seem to me that cardiac output, not stroke-volume, would be important for blood delivery to muscles. For example if my stroke-volume is lower than yours, but my heart beats faster than yours, I may have a higher cardiac output (ie volume of blood pumped per unit time).

Do I misunderstand?
Joe

To go back to my previous comparison, HR is unlikely to differ between a group of cat. 3s and pros, so differences in cardiac output are primarily influenced by stroke volume.

Wayne666 · #21 12-13.-2007

Quote:

Originally Posted by doctorSpoc

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 · #22 12-13.-2007

Quote:

Originally Posted by Wayne666

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 · #23 12-13.-2007

Quote:

Originally Posted by doctorSpoc

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 · #24 12-13.-2007

Quote:

Originally Posted by Urkiola2

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 · #25 12-13.-2007

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 · #26 12-13.-2007

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

Quote:

Originally Posted by 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.

acoggan · #27 12-13.-2007

Quote:

Originally Posted by 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.

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 · #28 12-13.-2007

Quote:

Originally Posted by acoggan

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.

Quote:

Originally Posted by acoggan

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...

Quote:

Originally Posted by Urkiola2

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 · #29 12-14.-2007

Quote:

Originally Posted by acoggan

*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 · #30 12-14.-2007

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).

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode