The Biochemistry of Alactic + Aerobic Training - Mitochondrial Health and High-Power Aerobics
[This is part 8 of many about the details of Alactic + Aerobic training and why you should be doing it.]
The muscle fiber post sparked a few tangents for me. One was about metabolic flexibility. This one is about why A+A training actually does help train your aerobic endurance and power output.
When discussing the aerobic pathway, I mentioned that the rate limiting step isn't how much oxygen you can get to your cells, it's more about how fast the electrons which are ripped off of the oxygen are transported down the electron transport chain inside the mitochondria. So if one mitochondrion can only chug along so fast producing ATP, how do you get faster while staying aerobic?
Build more mitochondria!
Here's a not-perfect analogy because in the real world building more roads only creates more traffic. But let's pretend that's not true.
I have a bunch of cars in the left parking lot and I want to get them over to the right parking lot. The maximum lane capacity of any road is about 20 cars per minute regardless of the speed limit (I leave the proof as an exercise to the reader, but it's true!). That's a lot like the maximum transport speed of electrons in the transport chain inside the mitochondria. Only so many can come through in a certain amount of time. But what if we need more ATP in those slow, aerobic muscle fibers?
If I want to increase the rate at which I can get cars from one parking lot to the other, and I'm limited by how many I can stuff down any one road, my only solution is to build more roads. If I need more aerobically-generated ATP from my mitochondria, the only solution is to build more mitochondria.
That's exactly what we do in A+A training. The explosive 10 second work quickly depletes all of our ATP in all of our muscles. From the muscle fiber post: we go explosively so that we can recruit all of our fibers. And we go in short duration so that we don't get acid build up from the glycolytic pathway. Now we stop and do our fast-and-loose drills to recover. Since we're not actively working, we're going to primarily be using the oxidative, aerobic pathway to replenish the ATP.
At first, you'll notice that you need a long time to recover. It can be a couple of minutes to recover from 10 heavy swings for a newbie. That stress is enough to tell your body to start making mitochondria - the fancy term is mitochondrial biogenesis (which can be enhanced by burning good fats). Over time (if you don't force it) you'll notice that your recovery time decreases. That's the sign that A+A is working. You'll be getting more work done in a shorter time. But you'll be getting the energy from the clean burning aerobic pathway. That's a good thing! You get faster with less downside. That's why A+A training can help you with your aerobic performance - all without the need for your glycolytic acid bath.
This is easy - which is good if you need to not be sore when you leave the gym. But it's boring and you don't get immediate feedback that you're doing good work - which is bad for motivation. If you can pay attention to your body and your feelings of recovery, you'll notice that fitness is sneaking up on you - almost like strength sneaks up on you when you do a good strength training program.