BF's study in Bio Chemistry
 

So....let's have a discussion about bio chemistry, how different proteins and enzymes are involved in maximizing cycling, and how diet can effect training and performance.

So....lets start out with how muscles work.
http://skeletalmuscularsystem.suite1...uscle_contract

The contractile fibers within muscles are myosin and actin. As these fibers contract and move across each other, Adensosine Tri Phosphate (ATP) is converted to Adenosine Di Phosphate (ADP) which provides the energy for the fibers to contract.

http://www.bris.ac.uk/Depts/Chemistry/MOTM/atp/atp1.htm

So...we know as cyclist, that each time we push the pedals through a revolution, we are asking the muscles in our quads to contract, or the hamstring, and thus turning lots of ATP to ADP. In extreme cases, the ADP can be used as energy and results in AMP (monophosphate). In order to perform at peak efficiency, we need to be able to quickly replenish this ATP. This is the purpose of this thread. How can we maximize this replenishment? How can we pack additional glycogen in the muscles to eventually produce more ATP? How much Protein do cyclist need? Are there other dietary components we can concentrate on to improve our performance.

ATP production:

ATP is produced in cells primarily through the electron tranport chain which is fed by the Krebs cycle (aka Citric acid cycle).

http://users.rcn.com/jkimball.ma.ult...spiration.html


Carbohydrates are consumed and converted to glucose, primarily in the liver. This glucose is converted to pyruvic acid thru glycolisis.
http://users.rcn.com/jkimball.ma.ult...lycolysis.html
Which results in NADH and FADH. NADH and FADH serve as a substrates in the electron transport chain. Here the NADH is subjected to NADH dehydrogenase then Cytochrome C Reductase and finally Cytochrome C Oxidase.

The Krebs cycle releases 2e-, and the electron transport cycle releases 4e- such that each molecule of pyruvic acid produces 6e-.
During the process of releasing the electrons, the Hydrogen is stripped from the NADH and FADH molecules and are pumped to the intermembrane space of the mitochondria. This hydrogen pump creates a voltage gradient, which essentially acts like a battery.

So, how does ATP get made?
Well, the battery just created by the hydrogen pump results in creation of some ATP.
To make a long story a little shorter, 38 molecules of ATP are created for each molecule of Glucose.

keep going, I'm right there with ya.

or you could just ride the bike

Typically, many athletes believe that the "quantity" of carbohydrate eaten determines its glycogen building potential. I think there is new evidence that glycogen building is "rate dependent" - meaning that glycogen restoration requires time as well as calories.

Other than that, knowing when and how much to drink is terribly important to any aerobic event that lasts longer than 40 or 50 minutes. Protein requirements are individual in nature, advice would be BS.

riddle me this:

What are the tums doing
to my ion channels ?

one step at a time...this is meant to be an exercise in studying how all this works, and what the effects are of different things. Its meant to be educational for all involved. Let's finish the Krebs cycle and how glycogen is built and converted to ATP. Then lets discuss the enzymes involved, and the effects of protein. And of course fat...mono- and poly-saturated as well as saturated. Omega3's vs. Omega6's vs Omega9's. Eicosanoids and inflammation. And Vitamins and minerals. And then supplements (which I would classify your tums as).

Skip to the Conclusions portion.

conclusions:
- ride lots
- - Eddy Merckx

there's a lot to talk about, everything above looks pretty good :)

to get it out of the way: lactic acid fermentation

muscle cells make ATP through LA fermentation when O2 is scarce (sugar catabolism outpaces the need for oxygen). ATP is produced by substrate level phosphorylation, pyruvate accepts the elections for oxidizing NADH to NAD+ so that glycolysis can continue..

the end product is lactate, which improves muscle performance. lactate used to be thought as the cause of muscle pain and fatigue.. Lactate cause neither DOMS nor acidosis. And, you're ability to clear lactate (to convert it back to pyruvate) is reliant on your liver.

Increased levels of potassium and "leaky" calcium channels may be to blame. (so curse K+ and Ca+, not LA) :)

why is it,

that I can ride equally well, on a diet of water and squirrel meat,
or water and donuts ?

Pick something that interests you and let’s discuss that, as biochem as a topic is way too broad. We could go 20 pages on just one of these areas.

Or more likely you don’t really want a discussion at all; instead you want to play professor on the interwebs.

umm....this is more for my learning than anything else. I outlined what I would like to explore. And yes, bio chem is an incredibly broad topic....but I'm trying to focus on ATP production and supporting systems.

Carry on professor, still looking forward to the conclusions of what type of food I should be eating to train.

It is interesting to note that the ATP is converted to ADP when the myosin head returns to its detached position. The energy from ATP is needed to release from the actin protein so muscle can rest. The mysoin actin cross bridge is broken this is because another ATP has attached to the myosin head, which is then broken down allowing the myosin head to return to its resting state.

This is why in rigour mortis a persons body goes stiff, there is not ATP available to allow the muscles to relax.


Many have mentioned a window that is available after exercise. During this time if protein is consumed the uptake of carbs is enhanced. This is probably due to the fact that protein will also raise insulin levels in the body. So there is a synergistic effect on insulin by carbs and protein.

This is where potatoes can come in real handy. Make a potato before heading out. When you get back consume some easily digestible protein and the potato. The potato will spike your insulin and decrease the amount of diabetogenic hormones that catabolise muscle. At the same time the protein is available to rebuild muscles.

Muscle contraction stimulates GLUT4 receptor presentation without insulin.

Thank you for mentioning that that is why exercise helps control blood glucose levels, but I am not sure why you mentioned that. My statement was referring protein intake and insulin.

It is interesting to note what GLUT4 receptors are. They present on the interior of the cell and serve as the mechanism to transport glucose into the cell. When insulin is present more receptors will be made available to the cell membrane to transport glucose into the cell. Like Enthalpic said, this action is also present during muscle contraction, allowing glucose to enter the cell during times when insulin secretion is repressed by exercise and the diabetogenic hormones that it produces.

can you explain the term "diabetogenic"? Sounds like it would be something that leads to diabetes, but the way you are using it leads me to think it means catabolic.

Somebody help me out with the carb/protein thing. Sure I've seen it recommended everywhere as common wisdom, but the one article review I read pointed out that there's only 1 study that looked at it, and their error was they didn't control for constant total calories.

So the subjects that had protein/carb mix, took in more calores than the carb-only subjects.

Have there been more conclusive follow-up studies?

You are right they are catabolic.

Diabetogenic hormones are the ones that increase blood glucose levels, or do the opposite of insulin and sex hormones. Like glucagon, which signals the liver to break down glycogen into glucose. The glucocorticoids signal the body to break down protein and adipose. The catacholamines, (nor)epinephrine are also diabetogenic.

So any hormone or process that is catabolic that increases blood glucose is considered diabtogenic.

Your paragraph began with exercise’s effect on glucose metabolism. It sounded as if you were hypothesizing that the reason behind the enhanced post-exercise glucose uptake was due to additional insulin, when it’s not actually necessary.

That’s why the “window” is so groovy. Normally you need insulin to trigger the GLUT4 presentation, gluc uptake and the resulting protein signaling cascade. After exercise you can get the gluc uptake and cascade without insulin; as I’m sure you know.

OK I got you, but this is part of the reason for enhanced glucose uptake, the insulin acting with fact that the muscles are more receptive to glucose because of the 2 conditions working together providing optimal conditions.

I can also see how the post exercise condition would need less insulin to do the same work. The fact that glucose levels are being lowered quickly without insulin would decrease the amount of insulin needed to absorb glucose.

I was also trying to explain why protein can enhance glucose uptake. Protein itself will raise insulin levels, so there is a synergistic effect. glucose and protein causing the body to release insulin and the fact that the muscles are more responsive to blood glucose related to GLUT4 presentation secondary to muscle contraction.

So Enthalpic, I know that you have said that insulin is not needed post exercise but does this mean that it is not secreted (in more than the basal amount that is always present), because of the GLUT4 presentation? Does the fact that there is more GLUT4 presented have an effect on insulin secretion directly, or is it due to the fact that increased GLUT4 presentation would cause a decline in blood glucose realted to the fact that it is being absorbed into the cells?

Inquiring minds want to know.

There's a lot on this subject, :) just gotta decide which is best.

http://www.jissn.com/content/5/1/24

http://www.acsm-msse.org/pt/re/msse/...195629!8091!-1

PubMed has a lot on it. Really though, you should eat towards quick recovery 24/7...

Tarnopolsky, et al. found in '88 (dunno if there's a more recent study) that the "Endurance Athlete" group reached a nitrogen balance (theoretically the point of sufficient protein intake) at 1.37 grams per kg of body weight per day.
(That's a lot of protein.) :thumb:

It all comes down to improved insulin sensitivity; after exercise you can get similar to “normal” uptake with less insulin, or more uptake with the same amount of insulin (provided you have eaten enough carbohydrate).

As for extra insulin production, I am not certain but I doubt it. With all the glucose uptake already going on additional insulin production would put you at risk of hypoglycemia. Protein / AAs may complicate this in that you may see more insulin after a post-exercise Carb&Pro feeding when compared to a post-exercise Carb only feeding, but I doubt you would see extra insulin if you compared it to a rested Carb feeding. So it’s not really more than normal, just more than the exercised control.

What do you think?

Has anyone done a study with an Insulin clamp to measure serum insulin levels after comparable exercise and intake of carb and carb/protein to see if more insulin is what's going on?