 Today, we'll take a look at the three energy systems that exist in the body and how they relate to running. Let's take it all the way back to the very basics of movement. How do humans move? Humans move by skeletal muscle, pulling on the bones and moving us, basically. That's why my arms are moving now. This is because my biceps is contracting. It's pulling the bones, pulling the skeleton. So muscles contract and produce movement. But how do these muscles contract? What is it that fuels the movement? Well, we have three main energy systems in the body that provide energy in the form of chemical energy that can then be converted to kinetic energy, which is movement. These three systems are creatine phosphate system, also known as the phosphogen system. There's the anaerobic glycolysis system. And then there's the aerobic oxidative energy system as well. So we have three energy systems. And I'm going to just quickly touch on each one of them. Creatine phosphate is the system that we use when we're doing short sprints. So we're talking 5 seconds, 10 seconds, maybe up to 20 second sprints. So it's when you're watching the 100 meter dash or the 200 meter, the main fuel source for that duration is creatine phosphate. Of course, the actual movement in the muscle is produced by something called ATP, adenosine triphosphate, without going too deeply into the muscle biochemistry. The ATP is sort of the energy currency. But in order to produce ATP, we need fuel. And creatine phosphate is like a reservoir of phosphates, which is a high energy molecule, we could say. And it quickly replenishes the ATP stores. So the easy way to put it is, if you're just needing quick energy for like 10, 20 seconds, you have a pool of energy in the form of creatine phosphate. So that's your sprinters system. Next up in line is the anaerobic glycolysis system. This is the system that you're using all the time. I mean, we're always using all the systems to some extent. But typically, the most of the energy for races lasting between 30 seconds and up to a couple of minutes, most of the energy for those durations of work come from anaerobic breakdown of fuel. So we're talking carbohydrate in the form of glucose or glycogen. And it's sugar basically, and it's literally being broken down incompletely. So it's anaerobic, which means it's without oxygen. So it's a fairly quick way of breaking down glucose, breaking out sugar in order to extract the energy, produce ATP, and then the ATP is involved in the muscle contraction. So if we're dealing with the 400 meter sprint or the 800 meter, especially, even some of the faster ones, like 1500, 3000, even up to 5000 and up, there is some contribution of anaerobic metabolism, even in a marathon. But typically, you know, 800 meter, for example, has a lot of anaerobic contribution. And it's basically sugar being broken down quickly to produce ATP. But there's a byproduct there, which is lactic acid, which differentiates into lactate and hydrogen ions. And those hydrogen ions, they create a acidic environment in the muscle. So it's kind of like when your car is burning in complete combustion, there's a lot of smoke and soft, maybe that's what it's called. It's not a clean burning fuel. Well, it's kind of like the same thing when you're dealing with anaerobic glycolysis. It's breaking down the sugar because we need it quick. But it's also creating some byproducts and it's not 100% efficient. Our last energy system is the most important one for anyone doing long distance running, which means anything longer than two minutes in our duration. And so we're talking 1500 meters, mile, 3000 meter, 5000, 10,000, half marathon, marathon, ultra marathon. Long distance running endurance activities are mostly fueled by the aerobic system. And the aerobic system breaks down carbohydrate and fat, takes it into the mitochondria. So inside the cells, so far, the creatinine phosphate system and the anaerobic system actually breaks down the fuel inside the cell, but in the cytosol, which means just the cellular, the intracellular fluid. Whereas the aerobic metabolism takes place inside the mitochondria, which is an organelle inside the cell. So this is like a little energy factory and everything that happens in there is really efficient, okay? We get a lot of ATP out of one glucose molecule or a fat molecule. As opposed to when we're doing anaerobic glycolysis, we're not getting as much ATP out of it. As I said, it's less efficient, but it is faster because aerobic metabolism requires oxygen, hence the word aerobic. So oxygen needs to come from the lungs, from pumped by the heart, out in the blood, diffuse into the muscle cells and get into the mitochondria in order to participate in the processes of oxidative breakdown of carbohydrates. In fact, in order to produce ATP and then the ATP is involved in the actual muscle contraction. So a simple way to put it, if there's enough oxygen and you have enough time to produce movement because the movement is slow, you're able to use the aerobic system. It's very efficient and you can go for very long on that system, but it needs to, it's a little slower than the other system. So if you're sprinting and your muscles are just going and you need energy now, you can't rely on the aerobic system. It's not fast enough to produce energy. There's too many steps that has to go, it has to go through in order to produce those ATP as opposed to the creatinine phosphate system, which is just one reaction, creatinine phosphate just, bam, creates an ATP molecule exactly when you need it. So there's a, it's essentially a time difference, really fast sprints, creatinine phosphate, long sprints or, or you know, one, two, three, four minutes of duration, a lot of anaerobic contribution, which is a faster system than the aerobic one, but slower than the creatinine phosphate system. And last but not least, for anything long distance, we're dealing with the aerobic system for the most part. How to train those systems, that's a topic for a whole different video. But for now, I hope that gave you sort of an overview of the three energy systems in the body. And I know we got a little bit technical today. That's the point of this video, really. I just wanted to touch on some of the technical aspects of fuel metabolism in the human body. If you have any questions, of course, you could always send me a message on the LoneTrail Facebook page, or you could go to my website, mggcoaching. There's a link in the description to set up a coaching session, to explain this for you further, or maybe help you with your training, anything like that. In the meantime, hope your running is going well. Hope you're having a great day. Post a comment, subscribe, and I'll see you in the next video. Bye.