You know what I mean. Coaching is a scientific-based activity but it's not science. It's much like engineering, a plane needs to fly and engineers make it fly even though they might not understand every factor that makes it fly.

---

-
"Yeah, no one likes a smartass, but we all like stars" - Thom Yorke


smartasscoach.tri-oeiras.com

I totally agree that gylcogen sparing is important since fuel depletion causes fatigue. Taking the cadence numbers of your example, I assume that the higher one also delays fatigue by producing less hydrogen ions (lactate), that interfere with Calcium/Troponin coupling, PFK, etc.

I'm not saying I have proof for the following, just something else to take into considerations: What about neuromuscular fatigue? *If* it really is a limitation to performance, could it be that the higher cadence cause more neuromuscular fatigue compared to the lower one? Just another thought...

---

�The greater danger for most of us is not that our aim is too high and we miss it, but that it is too low and we reach it.� -Michelangelo

MoodBoost Drink : Mood Support + Energy.

 

1 o'clock is 30 degrees past the 12 o'clock mark with
3 o'clock as the 90 degree mark, is the crank that
full 30 degrees past 12 o'clock. Why not use a photo
with a clock face behind the cranks when advertising.

[b]Check out the Simulator page on [url "http://www.RotorCranks.com"]www.RotorCranks.com[/url][/b] [/reply]



I had a look at the simulator page, they have not
even got the crank setup correct, they are supposed
to be in alignment in the 9 - 3 o'clock position.
I used a transparent clock face and placed it over the cranks, when the lower crank is at 6 o'clock, the
upper crank is only slightly over one and a half mins.
past 12 which is less than a third of what is being
claimed in advertising.

RVP wrote: You seem to be mixing up slow twitch fibers and fast twitch fibers - it is the former that are associated with a higher capillary density, and which were present in a higher percentage in the group 1 (high performing) cyclists who generated higher peak forces.

No, I'm not mixing up fast-twitch and slow-twitch fibers. Didn't the study say that not only did the high performing cyclists have more fast twitch fibers, but, they were better vascularized (I believe he said 23% better...I'm simply pulling this from memory, correct me if I'm wrong...as if I needed to say that ;) ) due to long term endurance training of their fast twitch fibers? If it did say this, it simply shows blood glucose was more available to thier fast twitch fibers due to their well-developed blood supply, allowing those fibers to work harder before depleting muscle glycogen....so these cyclists could "afford" to generate higher peak forces. Seriously, this isn't some weird off-base idea, is it?

As I said, unless the study were done using each cyclist using first one cycling style, then the other cycling style, and comparing each cyclist's results using each style...it isn't a study that proves one style is "better" than another. Right?

Thanks again for helping us better understand what may be going on.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

I think it may be. It is my understanding that blood glucose is not readily consumed during exercise.

Greater capillary density would however allow the rider's slow twitch fibers to work longer and harder before fibers that are less oxidative in nature would have to be recruited to sustain the effort.

After sixty years of funded research by physiologists,
biomechanical experts etc., what has the cyclist
gained, nothing except that interval training and
drugs have most to offer.

Winkle wrote: "Coyle used to think so. Then he got funding from the USOC, studied a slew of cyclists while they pedaled with and without toeclips and while they were running on a treadmill set at 10% grade, used instrumented force pedals to measure the actual forces being produced, etc., etc., etc., and finally convinced himself that this "spreading the work around" hypothesis was dead-ass wrong."

Here is my problem with this analysis NOW. This study was done before it was possible to effectively train the cyclist to spread the load around. Now that it is possible, until this cohort is studied, this conclusion is suspect, as the concept makes good engineering sense. Further, anecdotal data suggests that as people learn to spread the load around they get faster, not slower.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Is that an oxymoron?

[reply]
[reply]
After sixty years of funded research by physiologists,
biomechanical experts etc., what has the cyclist
gained, nothing [/reply]

Could that be because pedaling a bicycle is a very simple motor control task, such that simply doing what comes naturally is sufficient? [/reply]



NO, it's because that's what all of them have been told and believe.
The breakthrough came in cycling back in the sixties,
but because all experts of that time were so
brainwashed in the traditional ways of cycling, they
could not recognise that fact. Little has changed since then, coaches from one generation to the next
continue to believe that traditional ways are best.
The UCI rules are a typical example of this,
innovators are either banned or frowned upon.

JustCurious wrote: It is my understanding that blood glucose is not readily consumed during exercise.

Well, one of us is wrong on this idea...maybe RVP will help us out. It is my understanding that blood glucose IS readily consumed during exercise, so long as the intensity isn't great enough to demand glycogen consumption. Rip, which idea is correct? Remember, we aren't talking about VO2 max intensity....but Sub-VO2 max intensity.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

Boy, will I bookmark this post to be used as later evidence (#627). Oh, wait, forget it. No body knows who you are so when evidence arises to prove you wrong, all yu have to do is change your moniker, claim you knew it all along, and no one is the wiser.

My, how much easier to be so confident in your position when you have nothing to lose.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

RVP wrote: Didn't the study say that not only did the high performing cyclists have more fast twitch fibers They actually had more slow twitch fibers.


I'll have to go back and re-read it, I thought that he said they had more fast-twitch fibers, but they were better capillarized.


Then I wrote: As I said, unless the study were done using each cyclist using first one cycling style, then the other cycling style, and comparing each cyclist's results using each style...it isn't a study that proves one style is "better" than another. Right?


And RVP replied:
In a prior study, Coyle et al. measured the VO2max, heart rate, blood lactate threshold, and perceived exertion of low and high performing cyclists both with and without toe clips. Despite completely eliminating their ability to pull up, or even more than slightly back, this intervention had no effect on the observed physiological responses, such that the between-group differences remained. When the subjects were studied while running up a steep grade on a treadmill, however, the blood lactate threshold of the low performing cyclists improved from 66 to 82% of VO2max, whereas the blood lactate threshold of the high performing cyclists did not change signifcantly (82 vs. 85% of VO2max). Assuming that the low performing cyclists of this study pedaled similarly to the group 2 cyclists of the 1991 study (which may not be correct), then these longitudinal data suggest that attempting to actively pull up on the pedals is detrimental.



Of course, we don't know if your assumption is correct, as you said. Another thing that bothers me, it seems so much of these studies are done with athletes exercising at workrates approaching VO2 max. Exercise at VO2 max can be different than exercise at sub-maximal intensities, as VO2 max exercise is somehow cardio-vascular system limited (the chicken or egg doesn't matter here, let's don't get into why the limit seems to be cardiovascular at VO2 max), instead, it is glycogen depletion that is the limiter at sub-maximal intensities, just as you and I agreed in an earlier post.

Would you agree that VO2 max intensity dynamics and sub-VO2 max intensity dynamics could be different enough that one study's findings doesn't necessarily apply to the other? Sure seems that way to me.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

JustCurious wrote: It is my understanding that blood glucose is not readily consumed during exercise

J Sci Med Sport. 1999 Oct;2(3):181-9. Related Articles, Links
Physiological determinants of endurance exercise performance.

Coyle EF.

Department of Kinesiology and Health Education, The University of Texas, Austin, USA.

Performance in endurance events is typically evaluated by the power or velocity that can be maintained for durations of 30 min. to four hours. The two main by-products of intense and prolonged oxidative metabolism that can limit performance are the accumulation of hydrogen ion (i.e. lactic acidosis) and heat (i.e. hyperthermia). A model for endurance performance is presented that revolves around identification of the lactate threshold velocity which is presented as a function of numerous morphological components as well as gross mechanical efficiency. When cycling at 80 RPM, gross mechanical efficiency is positively related to Type I muscle fiber composition, which has great potential to improve endurance performance. Endurance performance can also be influenced by altering the availability of oxygen and blood glucose during exercise. The latter need forms the basis for ingesting carbohydrate at 30-60 grams per hour during exercise. In laboratory simulations of performance, athletes fatigue due to hyperthermia when esophageal is approximately 40 degrees C, in association with near maximal heart rate and perceived exertion. It is likely that the central nervous system is involved in the aetiology of fatigue from hyperthermia. Dehydration during exercise promotes hyperthermia by reducing skin blood flow, sweating rate and thus heat dissipation. The combination of dehydration and hyperthermia during exercise causes large reductions in cardiac output and blood flow to the exercising musculature, and thus has a large potential to impair endurance performance. Endurance performance is optimized when training is aimed specifically at developing individual components of the model presented and nutritional supplementation prevents hypoglycemia and attenuates dehydration and hyperthermia. Indeed, the challenge at the transition to a new millennium is to synergistically integrate these physiological factors in training and competition.
Yes, glucose is readily consumed during exercise, if I read this correctly.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

This is what I mean when I say VO2 max exercise has different energy-consumption dynamics when compared to sub-VO2 max exercise:



Am J Clin Nutr. 1995 Apr;61(4 Suppl):968S-979S. Related Articles, Links
Substrate utilization during exercise in active people.

Coyle EF.

Department of Kinesiology and Health Education, University of Texas at Austin 78712.

When people walk at low intensity after fasting, the energy needed is provided mostly by oxidation of plasma fatty acids. As exercise intensity increases (eg, to moderate running), plasma fatty acid turnover does not increase and the additional energy is obtained by utilization of muscle glycogen, blood glucose, and intramuscular triglyceride. Further increases in exercise intensity are fueled mostly by increases in muscle glycogen utilization with some additional increase in blood glucose oxidation. Muscle glycogen and blood glucose contribute equally to carbohydrate energy production over 2-3 h of moderate-intensity exercise; fatigue develops when these substrates are depleted. Active people can deplete muscle glycogen with 30-60 min of high intensity, intermittent exercise. When the ingestion of dietary carbohydrate is optimal, it is possible to resynthesize muscle glycogen to high concentrations in approximately 24 h, which is the major factor in recovery of exercise tolerance. However, this requires that a 70-kg person eat at least 50 g carbohydrate per every 2 h, beginning soon after exercise, and ingest 500-600 g in 24 h (ie; approximately 7-9 g/kg body wt). Carbohydrate foods eliciting high glycemic and insulinemic responses promote more rapid glycogen resynthesis than do foods eliciting lower glycemic responses. Therefore, foods ingested for energy before, during, or after exercise should be classified according to their glycemic index. Although carbohydrate ingestion before and during exercise adds exogenous substrate to the body, it usually attenuates plasma fatty acid mobilization and oxidation.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

"It is my understanding that blood glucose is not readily consumed during exercise. "

what do you mean with that? just because our body is pretty good at maintaining blood sugar levels, it doesn't mean that those aren't consumed. When the body uses glycogen stores from the liver, those are broken down. There is no point in having the liver store glycogen UNLESS there is a way to translocate those stores to the working muscles. That's when blood and its circulation come in.

Let's assume that liver glycogen are broken down to meet the fuel requirements at the working muscles. If you would measure blood sugar concentration during various times of that exercise bout, the reading might turn out to be always the same. That doesn't mean that the muscles don't use the free glucose in the blood. Of course they use those energy substrates. It's just that the body well maintains the blood sugar levels. In this case, consumption of blood glucose equals its replacement/glycogen breakdown from liver stores.

Take it a step further and deplete the glycogen stores. The contracting muscles still require energy and take up blood sugars. Since the depleted glycogen stores can no longer contribute to the maintenance of blood sugar levels, that concentration starts to decline. Reduction in the concentration of blood sugar = trouble..

---

�The greater danger for most of us is not that our aim is too high and we miss it, but that it is too low and we reach it.� -Michelangelo

MoodBoost Drink : Mood Support + Energy.

Dude,

Type I are 'slow-twitch' fibers. Type IIa and IIb are 'fast-twitch' fibers.

Sorry, should have been more clear. Glycogen and lactate are more predominantly consumed by working muscle than is blood glucose. Unlike other tissue that uses glucose more readily, the rate of blood glucose consumption by muscle tissue is relatively limited and I'm not sure that a greater capillary density would increase muscle uptake of glucose and spare glycogen.

This is stretching my memory, but according to the 'glucose paradox', glucose released into the blood from dietary carbs is used by muscle tissue to either synthesize glycogen or produce lactate. Blood carries the unused lactate back to the liver to produce either glucose or glycogen. Unlike O2 uptake, I don't know that glucose uptake is limited by Q to the muscle. That's all I was trying to say.

You stated, "Since the depleted glycogen stores can no longer contribute to the maintenance of blood sugar levels, that concentration starts to decline. Reduction in the concentration of blood sugar = trouble.. "

I think that's backwards. Muscle glycogen doesn't contribute to blood sugar levels. Blood glucose is used to form (directly or indirectly) liver and muscle glycogen.

But that's just a 'layman's' version.

Thanks guys. I was having a terrible night. Personal problem. It is keeping me up. For the first time in several years I can't fall asleep. I need to get up early for a long ride. It is 12:30 Alabama time. Just ready pages 8-12. The cardio stuff really made my eyelids heavy. Think I'll sleep now. Thinking happy thoughts of that old seven speed I'll ride tomorrow. Got Suntour cranks. No study or statistics to show whether they are better than power cranks or whether V02 max improved since last week or whether my capilaries get clogged by the gu I'll take. I'm almost asleep now. Cardio, anesthesiology, Groggin, Tibbs, powercrank, efficient cycling, epidemologsssyg, 40%%%%%%%%%%%%%%%, d;alkne'[wiofw'fJejfc'ei9jf'NJhnjf ;'4e'[]

---

________
It doesn't really matter what Phil is saying, the music of his voice is the appropriate soundtrack for a bicycle race. HTupolev

You're right!

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

From Coyle EF, a few posts back...Muscle glycogen and blood glucose contribute equally to carbohydrate energy production over 2-3 h of moderate-intensity exercise; fatigue develops when these substrates are depleted.

This doesn't address your question about the rate of blood glucose consumption by muscle tissue being relatively limited and whether or not greater capillary density would increase muscle uptake of glucose and spare glycogen. I understood that as long as activity was easy enough, fatty acids were consumed. Then, as activity increased, blood glucose was mostly consumed (fatty acids are still being consumed as before...they don't shut off just because glucose is being utilized), as activity increased even more, glycogen was mostly consumed due to a lack of sufficient readily-available oxygen (and none of this is all-or-none, but just relative terms, you may still burn some glycogen at very easy efforts, just very small amounts; sort of like aerobic and anaerobic pathways actually occuring simultaneously much of the time)...and lack of sufficient readily available oxygen is often directly equated with blood flow...this may be a chicken-or-egg thing, which is it, blood flow too low to deliver enough oxygen or not enough glucose, or both?

Another layman's view...I don't know if it is correct.

I think you are also right that muscle glycogen doesn't contribute to blood sugar levels. Blood glucose is used to form (directly or indirectly) liver and muscle glycogen. But, it's my understanding that if you either increase intensity or drop blood glucose too much, the muscle then must mostly use glycogen (much less efficient) instead of glucose. The muscle can experience low glucose availability by having too little blood carrying a normal level of glucose to the muscle, or if there were a drop in blood normal glucose concentration.


Again, so many studies look at VO2 max intensity exercise, you hear much more about glycogen and lactate being used my working muscle. It's the sub-VO2 max state when glucose-utilization plays a larger role in working muscle.

---

Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

One thing that hasn't been addressed regarding fatigue, which is most likely an energy production enzyme and substrate problem, is the effect of training. It seems to me that training can have a huge effect on how one fatiguees and the types of fuel that one burns when one is exercising and approaching significant fatigue levels.

I think this is very complicated and any study that looks at this is probably not worth much unless it controls for the kind of training the people do.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

 Congrats Frank, I see your PC's got a recommendation on Cyclingnews. Q&A section.