When does it go from aerobic running to anaerobic?

ok, here is why I don't believe in max VO2. It is measured in the lab as a culmination of stepped exercise, where they start out low-key and gradually increase the intensity. When they increase the level but O2 consumption remains the same, they say, "well, that's the O2 max then." This seems to presume that it would still have been the max if it had started out full-bore like any real-life race under 10,000m, which is silly considering that anaerobic muscle fatigues much more quickly than aerobic, and also is critical to maximizing the rate of O2 unloading into muscle.

The dependence of hemoglobin-O2 affinity on pH is a local phenomenon on the capillary level, not just some generalized issue of how acidic the overall muscle is. A pH gradient exists within the capillary that causes O2 to unload and CO2 and cations to be picked up in exchange. Most muscle fibers can metabolize, to some extent, both aerobically and anaerobically, so that the most direct way for a muscle fiber to increase its own oxygen uptake should be to operate anaerobically as well to lower the pH in the particular capillaries supplying it.

But after 8 to 10 minutes of stepped exercise, any muscle fiber being used aerobically has likely lost its peak anaerobic function to fatigue. At this point acid buffering capacity is usually overwhelmed, and acidosis overtakes the muscle and interferes with its function. One might suppose that the pH at this point is the lowest possible and must correspond with the max O2 unloading rate and thus max VO2. But what if, during the earlier stages of exercise before high anaerobic metabolism can overflow buffering, the pH can drop even lower in the capillaries supplying the working muscle without impairing it? Thus lowering local HB-O2 affinity even further, and allowing a higher aerobic output from that particular muscle than it can produce during the acidosis-impaired later stages.

And if you've run many 400's or 800's, you've probably experienced altered running form at the end. As muscles shut down you have to find other muscles to run with instead. This may occur during VO2max testing too. The way I see it, after several minutes, you're using muscles that have been reduced by fatigue and local acid-buffer overflow to running on oxygen, at which point the only way you can handle the next treadmill speed is to switch to alternative muscles. Because newly-activated muscles work anaerobically, O2 consumption stays the same. But how much O2 could the original muscles have used if they weren't fatigued anaerobically yet? Besides the possibility of lower capillary-level pH and faster O2 unloading, I see no reason to suppose that limits to the anaerobic function of a muscle fiber wouldn't impair its aerobic function too. A tired muscle is a tired muscle.

There is also the matter of ammonia-based fatigue. Anaerobic muscle work causes rapid breakdown of muscle tissue which is likely responsible for feeling fatigued.

http://www.ncbi.nlm.nih.gov/pubmed/20138956

This affects the CNS and, who knows, it might play a role in shutting down the muscles and their O2 use after prolonged exercise.

Much more simply, I believe fresh muscles can use more oxygen than tired ones. And I always feel like I'm using oxygen faster in an 800 than a 3000.

since you're interested in this metabolic stuff, here's a study I posted once before

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3824146/

I'd say its when the nipple makes it first appearance.

Nice little read Wigins.

I share your dislike for "VO2 max". When you see it in the literature it is usually implied that "oxygen uptake is limiting performance", whereas I think the correct interpretation is "this is what your oxygen uptake is when your performance is limited (by whatever the limiting factor is)".

The direction of causality is key as always.

hobby jogger^3 wrote:

For me, it tends to switch to anaerobic at the point in a race when all the fast guys decide it's time to start racing. Then when I give up a few minutes later and slow down it's aerobic again.

Best reply so far.

Limey UK Runner wrote:

Nice little read Wigins.

I share your dislike for "VO2 max". When you see it in the literature it is usually implied that "oxygen uptake is limiting performance", whereas I think the correct interpretation is "this is what your oxygen uptake is when your performance is limited (by whatever the limiting factor is)".

The direction of causality is key as always.

Elite athletes have better oxygen economy don't they?

Everyone seems to ignore this point. Endless BS about EPO supposedly increasing oxygen supply also ignores this point.

yes, but wrote:

Everyone seems to ignore this point. Endless BS about EPO supposedly increasing oxygen supply also ignores this point.

This is a bit outside my comfort zone but my two bits is that you are right to call BS on the performance benefit of EPO being down to enhanced oxygen supply. It seems much more likely to me that it is due to enhanced CO2 extraction or some other effect you get as a result of having more young red blood cells.

There was another thread around that subject recently but I didn't get much past the first page because of the pissing contest that quickly developed.

Yes it is like they have the definition sort of reversed. I never liked the "max" in there, perhaps it should be V02rate or something.

The thread was sabotaged by a certain troll who was pretending to be an exercise physiologist.

EPO isn't a physical enhancer. It's all in the athlete's head. Efficiency is what superior performance is all about.

50 years ago, everyone was obsessed with methamphetamine. To say that it wasn't a PED woud have been to court ridicule. Times change, attitudes change.

Doesn't boost oxygen, but rather red blood cell or erythrocytes, which are the oxygen carrying cells that transport them to the tissues. There is no question that EPO does that.

Quindim wrote:

Sprint coach wrote:

There is an aerobic contribution to sprints. Small, but measurable.

Yeah, it's somewhere in the vicinity of 4-8% for 100m, i.e. negligible. It'd be interesting to know what the aerobic contribution to 60m or 40yds looks like, if it exists at all.

Since when is 8% negligible?

Limey UK Runner wrote:

Nice little read Wigins.

I share your dislike for "VO2 max". When you see it in the literature it is usually implied that "oxygen uptake is limiting performance", whereas I think the correct interpretation is "this is what your oxygen uptake is when your performance is limited (by whatever the limiting factor is)".

The direction of causality is key as always.

VO2 Max certainly is a limiting factor. It is not the only limiting factor, but cannot be discounted based on how it is measured.

Other limiting factors in no particular order

Neuromuscular coordination

muscular strength

Running Velocity at Lactate Threshold

Running Economy

Injury Prone-ness

The list is long, but VO2 belongs on there and as such, tests for VO2 can have some value.

CoachB wrote:

VO2 Max certainly is a limiting factor.

Most people have no "VO2 Max". Only 14 % of average Joe and less than 50% of elite cyclists have a maximum level and not a peak. To say that a VO2 peak is a limiting factor is as ridiculous as saying that your 3k pr is a limiting factor for running a 3k.

no, no, no wrote:

CoachB wrote:

VO2 Max certainly is a limiting factor.

Most people have no "VO2 Max". Only 14 % of average Joe and less than 50% of elite cyclists have a maximum level and not a peak. To say that a VO2 peak is a limiting factor is as ridiculous as saying that your 3k pr is a limiting factor for running a 3k.

Agreed. One of the most comical things I have ever read in a paper was in that study of elite cyclists. When some were observed not to reach a plateau in O2 uptake the authors suggested that these elite cyclists were "unable to muster sufficient motivation" to go all out (or words to that effect). Hilarious.

This thread is awesome!! :) Very interesting to read!!

Anne Aerobic wrote:

Both systems are constantly used. It's not one or the other. It's a mix.

this^^^^^ f*ckin THIS!!!!!! i get so sick of the whole aerobic anaerobic thing its so stupid why even bother worrying about it? like what will this question even accomplish

Hunter S. Thompson wrote:

Anne Aerobic wrote:

Both systems are constantly used. It's not one or the other. It's a mix.

this^^^^^ f*ckin THIS!!!!!! i get so sick of the whole aerobic anaerobic thing its so stupid why even bother worrying about it? like what will this question even accomplish

I have to bite my tongue when people call something "anaerobic training" when it is clearly not anaerobic training.

Interestly the two types of training that have been linked to improving running economy ARE anaerobic in nature...short sprints and resistance training (heavy weights and plyos). Also, simply running a lot should improve economy as the more you practice any skill the more effecient you become.

V02max or V02peak is only as important as how you actually use that oxygen. What's your velocity? What are your limiting factors or supporting factors for that velocity? There are certain factors you are born with and cannot change (muscle insertion points, limb segment lengths), there are certain factors you can only partially change (limb segment mass), and many things you can change quite a bit through training (capillary and mitchondria density, muscle strength, power, reduced excess body motion).

Alan

Athletics Illustrated wrote:

Doesn't boost oxygen, but rather red blood cell or erythrocytes, which are the oxygen carrying cells that transport them to the tissues. There is no question that EPO does that.

Agreed, injecting EPO definitely increases RBCs but everyone and his dog assumes that this must boost performance. But actually elite athletes use oxygen more efficiently don't they? Why is this overlooked.

The obsession with so called 'performance enhancing drugs' is nothing but superstition. It's so ingraine in everyone psysche, that it's impossible to have a debate on the subject. People are either too ashamed and embarassed to have their belief questioned by simple logic and actual physiology that they react either in an aggressively negative way, or keep quiet.

The way i am seeing this is like:

Super Elite efficient athlete

- has a handful of super strong guys that can carry tons of stuff at once

Athlete taking EPO

- a couple dozen guys careering fewer things, but rate is fast because there is a ton of them.

* so logically if an athlete takes EPO and trains efficiently, they would have a TON of SUPER STRONG GUYS. moving all there things. (if you haven't guessed the guys are Red blood Cells and the "things" are oxygen molecules.)

One thing i'm not sure of though is the limiting factor of how fast and how much oxygen the muscles can absorb at a given time. and with that whats the bottleneck threshold where regardless of how much RBC you have delivering oxygen, that O2 absorption remains constant?

From what I have read, it seems to me that Vo2 max, is the point when the workload requires more energy to be produced faster then the required oxygen can be delivered and utilized by the muscles. We all know that how efficient and fast your body utilizes oxygen can be trained and developed. so logically training a pace that is near 100% your V02 max will adapt your body increase that maximum. The question I ask to anyone and everyone is how can we be sure what exactly is the bottleneck for each individual? The amount of RBC carrying Oxygen? The Carrying capacity of each RBC? or the metabolic rate at which your body can utilize said oxygen?

I'm just an average joe who likes reading and trying to understand the subject, i am coming from a logical perspective using information i have had access to. ijm just saying before we exclude anything and deem it superstitious we should look at every aspect of the matter.

thanks guys! if anyone can help me understand more, feel free!

yes, but wrote:

The obsession with so called \'performance enhancing drugs\' is nothing but superstition. It\'s so ingraine in everyone psysche, that it\'s impossible to have a debate on the subject. People are either too ashamed and embarassed to have their belief questioned by simple logic and actual physiology that they react either in an aggressively negative way, or keep quiet.

I do not agree with your statement, \"nothing but superstition.\" I don\'t think the World Anti-Doping Agency publishes documents that list banned so-called \"performance enhancing drugs\" without justification. WADA is funded by member nations and those funds are matched by the IOC. There are many millions of dollars at stake right there.

There is too much scientific evidence proving that anabolic steroids benefit power athletes like sprinters and weight lifters etc etc.

You think Russia will risk so much on a superstition?

Regarding EPO and RBC, if you have a higher red blood cell count, you have a higher oxygen carrying capability, there is no disputing that. When you are running for distance, what are your working muscles demanding? More oxygen.

Additionally, to test someone, find them positive, then ban them is a pretty drastic thing to do to someone\'s career, reputation and life based on a superstition.

So I am afraid you are going to have to do better than that to convince me that so-called performance enhancing drugs do not work and that their value is all a superstition.

I do think that there is some science indicating that the very best performing athletes are more efficient, but that doesn\'t mean they do not also benefit from taking PEDs.

Look at baseball a few years ago. Suddenly there were guys were breaking home run records all at the same time, Mark MacGuire, Sami Sosa, Barry Bonds, Jose Cansenco...coincidence that they all took anabolic steroids? Not!

I don\'t know how old you are, but research the East German doping machine of the 70s and 80s. Some of those women ended up getting sex reassignment surgery because they were turning into men.

Look at the lists for all-time greatest performance in the some different events, especially the womens - very suspicious stuff, like the top-6 women\'s 3000m times. So they never before or after have come close to these performances.

1 8:06.11 Wang Junxia CHN 09.01.73 1 Beijing 13.09.1993

2 8:12.18 Qu Yunxia CHN 25.12.72 2 Beijing 13.09.1993

3 8:12.19 Wang Junxia CHN 09.01.73 1h2 Beijing 12.09.1993

4 8:12.27 Qu Yunxia CHN 25.12.72 2h2 Beijing 12.09.1993

5 8:16.50 Zhang Linli CHN 06.03.73 3 Beijing 13.09.1993

6 8:19.78 Ma Liyan CHN 03.11.68 3h2 Beijing 12.09.1993

How about this century, nothing in the 1500m in the top-14:

1 3:50.46 Qu Yunxia CHN 25.12.72 1 Beijing 11.09.1993

2 3:50.98 Jiang Bo CHN 13.03.77 1 Shanghai 18.10.1997

3 3:51.34 Lang Yinglai CHN 22.08.79 2 Shanghai 18.10.1997

4 3:51.92 Wang Junxia CHN 09.01.73 2 Beijing 11.09.1993

5 3:52.47 Tatyana Kazankina RUS 17.12.51 1 Zürich 13.08.1980

6 3:53.91 Yin Lili CHN 11.11.79 3 Shanghai 18.10.1997

7 3:53.96 Paula Ivan ROU 20.07.63 1 Seoul 01.10.1988

8 3:53.97 Lan Lixin CHN 14.02.79 4 Shanghai 18.10.1997

9 3:54.23 Olga Dvirna RUS 11.02.53 1r1 Kiev 27.07.1982

10 3:54.52 Zhang Ling CHN 13.04.80 5 Shanghai 18.10.1997

11 3:55.0 Tatyana Kazankina RUS 17.12.51 1 Moskva 06.07.1980

12 3:55.01 Lan Lixin CHN 14.02.79 1h2 Shanghai 17.10.1997

13 3:55.07 Dong Yanmei CHN 16.02.77 6 Shanghai 18.10.1997

14 3:55.30 Hassiba Boulmerka ALG 10.07.68 1 Barcelona 08.08.1992

Performance enhancing drugs are very effective there is no doubt about it!