The Biochemistry of Alactic + Aerobic Training - Alactic Pathway


[This is part 3 of many about the details of Alactic + Aerobic training and why you should be doing it.]

So, I hope you believe me that ATP is the master energy source at the cellular level. When we use up ATP, we need to make more. The question is how do we make more.

This post is about the simplest way to replenish ATP - the phosphagen system, where we steal a phosphate from a creatine phosphate molecule that's lying around.

Recall that when we use up ATP, it's through this reaction: [ATP + Water -> ADP (adenosine diphospate) + P + acid + heat + energy], which creates ADP. We want to promote that diphosphate back to a triphosphate.

ADP + Creatine Phosphate + acid -> Creatine + ATP

In chemistry speak, we protonate the Creatine Phosphate to make Creatine and ATP.

Ok, that's pretty boring, and I normally stop there. But I learned about another pathway that takes over when we start to run out of Creatine Phosphate, but still need quick energy.

What if you have to ADP molecules lying around, you can steal one phosphate from one of them to make ATP.

ADP + ADP -> ATP + AMP (adenosine monophosphate)

I like to think of this as a reaction of last resort. Ideally you’d just be turning those ADPs back to ATP, but when you run our of Creating Phospate, your body decides that it would rather waste two ADPs to make one ATP and throw away that remaining AMP.

And if you're burning tons of ATP and leaving around a lot of acid, your body wants to get rid of that so it does this

AMP + acid -> IMP (we don't care about this) and NH3 (ammonia)

Blah, blah, blah chemistry, I know. I'm a chemist and this is getting tedious. But here's something to think about:

Why do you smell bad after a hard workout but not after sitting in the sun all afternoon (presuming that you're sweating in both circumstances)? Or why do your gym clothes smell so bad? It's the ammonia!

When you're sweating to cool down, that's basically just salt water. You're sweating to get an evaporative cooling effect.

When you're sweating in a hard (too hard?) workout, that's your body using sweat to get rid of a toxin - ammonia. That's what smells bad.

I would argue, that if you smell bad after a workout, that means you dug too deep into your energy demands. Your body isn't going to produce a toxin unless it needs the energy more than it wants to deal with the byproducts.

Key point: all of these reactions are already set up to be used. That is, you can just sprint or lift a heavy weight - right now! And then you can recover with the Creatine Phosphate and acid that's already there - there's nothing there that you can train, it's just chemistry.

How does this fit into A+A training? The first repeat - your first set of swings - uses up your ATP, then that ATP is regenerated with your Creatine Phosphate. Then comes the second set of swings, no more Creatine Phosphate left, what happens? That's where the other pathways (that can be trained) take over - done correctly, we'll regenerate our ATP with our mitochondria (the aerobic pathway).

Michael Deskevich