For improvement in recreational sports on up to professional, creatine is probably the single most depended on natural supplement. And I guess it deserves this lofty ranking considering it's marginally better than adequate and every other available supplement sucks lubed goat ass tubing.
Creatine was discovered in 1832 (Balsom, Soderlund & Ekblom, 1994) and has been researched pretty heavily since, such that virtually countless studies have now been conducted assessing its effects on every possible niche of athletic performance. Through all of these studies, about 70% or so reported statistically significant gains in strength and athletic enhancement, and a large portion of the remaining studies found gains that just fell short of statistical significance (Kreider, 2003).
Let's be realistic with what this means. Let's say half of these studies were conducted all sorts of poorly to back a biased agenda. We're still looking at more than a third of the available literature showing a statistically significant effect size. This is big news. This means at the absolute least that creatine does produce somewhat
of an ergogenic effect. This coupled with the absence of legitimate documented side effects (Lemon, 2002) has truly made creatine one of the most popular supplements ever to grace our sporty little market.
I therefore proclaim creatine as worth discussing. And in this discussion, we'll start with what it actually is. Then why it may or may not work how they tell us it does. But how it still works. Then we'll play with Tony and Jessica (Tony & Jessica, 2005).
Creatine is a natural compound your body is already routinely making pretty much every moment of your live from the amino acids glycine, arginine, and methionine. You store almost all of it in your skeletal muscle, and most of that ends up in the more anaerobic type II fibers (Casey, et. al., 1996). This makes complete sense considering the creatine phosphate energy cycle favorably fuels the recruitment of the more anaerobic type II muscle. It makes complete sense to me anyway. Basically the muscle fibers that use it, store it. It's pretty logical.
In order to assess the claims made by creatine manufacturers, we need to have a real solid understanding of how the body produces energy. So here goes: your body runs on ATP. That's what gives you the energy for everything you'll ever do. And you have some
free ATP just floating around waiting to be used to fuel your movements. Not much though. It's a heavy molecule. If you had enough to get you through the day you'd be like a thousand pounds. Maybe you are a thousand pounds. Lose weight. Either way, there's no way you can have enough ATP to support more than a couple seconds of activity, so instead, your body has ways of producing it. These are your energy cycles. Guess what the first one is? The creatine phosphate system. And I hate to even label this one a cycle because of how fast it is. It's basically one step to ATP. It's the absolute fastest way of generating ATP you have, and production speed is important. The faster you can produce it, the faster you can use it. The faster you can use it, the stronger and faster you are. You with me still?
Okay, after the creatine phosphate system, the next fastest energy cycle is glycolysis. This is where you start getting into standard calorie use, so it's a bit slower. It's still pretty fast considering your body is just breaking down carbohydrates as fast as it can to release the ATP, but it's a decent amount slower than the creatine phosphate system. And the last energy cycle is oxidative phosphorylation. This is the slow, aerobic energy cycle that uses your fat. And you get tons of ATP out of it, but it takes forever. So if you're relying on oxidative phosphorylation to produce your ATP, you're way weaker than you would be if you were getting your ATP from the creatine phosphate system. Does that makes sense?
This is where the claims for the effectiveness of creatine come from. Basically the claim is that, when you ingest creatine, it ups your creatine phosphate stores so that you can get faster ATP production for a longer period of time before glycolysis comes in and picks up the energy tab.
This makes complete sense given what we've discussed so far. But if this claim is valid, we would have to make a couple assumptions. First, that orally ingested creatine can reach the muscle unscathed, and increase the phosphocreatine stores. Second, we would have to accept that this new, increased amount would allow your body to depend more heavily on the creatine phosphate system in ATP production. Does this make sense?
Okay, let's assess these assumptions with an example. You running a 100 meter dash is our example. This is the creatine phosphate system's shining event due to the huge ATP demand, super super fast, over a short duration.
The gun goes off and you sprint as hard as you can for something like 10-15 seconds. 8 seconds if you're me. Then it's over. In order to perform your absolute best, you need the fastest ATP supply possible. Slower ATP supply means your muscles can't contract as fast or with as much force. Hence, you're slower. Faster ATP means a faster you. So your body does everything it can to give it to you as fast as possible.
In doing so, notice that your breathing doesn't really increase until the sprint is pretty much over. There's a reason for this. Your slowest energy cycle, oxidative phosphorylation is the only one that requires oxygen and your body has no interest in trying to fuel an all-out sprint with slow ATP. So the ways your body fuels the run are with free ATP, creatine phosphate, then glycolysis, and they happen in that order. Your free ATP gets you off the line, then the creatine phosphate system kicks in almost immediately, such that it is often grouped together with ATP and referred to as if they were the same thing. They're not, but pretty close. And once the creatine phosphate system kicks in, it basically becomes the majority ATP provider for several seconds until glycolysis steps in as the majority provider for the rest of the sprint.
Remember what the claim was for creatine's effectiveness? If ingested creatine increases the phosphocreatine stores and allows the creatine phosphate system to run for slightly longer, we would have faster ATP production for a longer period of time, and therefore better performance.
Also remember that we agreed that for this to happen, we have to assume that the body must be able to increase phosphocreatine stores and
be able to use those higher stores instead of turning the bulk of the ATP tab over to glycolysis.
We'll assess this. You just finished your 100 meter dash. Let's assume this was your very first time doing this sprint, and so your body used the creatine phosphate system to the best of its natural potential. When you're done with the run, notice how you're breathing like crazy. You're not even doing anything. Just standing there and breathing all fierce. There are a lot of reasons why you're doing this. You have to replace your oxygen stores in the blood and muscle, fuel your wildly-pumping heart, account for elevated metabolic processes, and so on. But another big reason why you're breathing all heavy is so that you can resynthesize the phosphocreatine stores you just used up during the run. This is important. If your body resynthesizes more than you previously had, it means that phosphocreatine levels are
adaptable, and you can
increase your stores. It turns out, this is the case. Slowly, but it does happen. And if you train to target this energy system for a couple years, there can in fact be measurable increases.
There is a slight problem though. More of a hindrance than a problem. Creatine phophoptase. It's an enzyme that prevents you from synthesizing additional phosphocreatine when you already have enough. That means if you want to raise the amount you store, you have to do it mostly on your own merit. Increasing the phosphocreatine supply without changing the demand gives you expensive pee.
That's not to say that creatine has no effect on your stores. Because it does. I wouldn't have expected it, but it actually does. If you really challenge your creatine phosphate energy system while supplementing ingested creatine, you can actually get a measurable change. Not as generous as the claims would have you believe (because the claims don't account for creatine phosphotase and use-based need), but certainly detectable increases. And since nobody would take creatine while not working out at all, we can assume that the majority of those who take it experience some level of an increase in phosphocreatine stores.
It might be a more considerable increase if you were to block creatine phosphotase, but neither creatine, nor any other supplement that exists can do that. So as is, the link between creatine ingestion and increased phosphocreatine stores definitely does exist, but it's not quite in the realm of being fantastic.
But for the sake of argument, let's say that it is. Let's say that you get a massive increase so that we can play out step 2 in the "in order for creatine to work by this mechanism" explanation in full glory. Remember part 2 is that this increase would allow you to use the additional creatine phosphate during the activity.
Let's go back to the example. The gun goes off and you start sprinting. All 4 energy cycles are immediately activated. Your free ATP is used predominantly first because it's obviously fastest. The creatine phosphate system goes into effect very shortly after because it's second fastest, and the free ATP is still being used at this point, it's just not as much of a contributor to the total. Then once glycolysis is up and running, which takes a few seconds, it becomes the primary ATP provider. At this time your creatine phosphate system is still contributing some ATP, but it's by no means the commanding force once glycolysis is in full swing. Then oxidative phosphorylation doesn't really get a chance to kick in until you're done running just because it takes so bloody long (i.e. slowest ATP production). If you ran for a while longer though, it would end up being a major contributor and glycolysis would slow down- but by the time that happens, you aren't really running too fast anymore. Regardless of how much fat you have, that's pretty much how oxidative phosphorylation is going to work. Regardless of how many carbs you have, that's pretty much how glycolysis is going to work. And likewise, regardless of how much stored phosphocreatine you have, that's pretty much how the creatine phosphate system is going to work. Outside of extremely low energy substrate levels where you're probably collapsing, the energy systems work in this pattern.
Glycolysis doesn't kick in because phosphocreatine stores get low. This is important to understand. Even after your first time sprinting, before any adaptation, your phosphocreatine stores are nowhere near depletion. If you actually depleted your phosphocreatine stores, you probably are or were dead. Rather than die, you just use a certain amount, mildly related to the total. So in the context of the sprint, you would essentially just start and finish with something like 10% higher phosphocreatine values than the previous norms. You'll use a little more than you normally would during the time glycolysis is running as well, because you can, but it won't be a huge change. All your energy systems work reasonably synergistically with each other, correlated more with timing than substrate levels. Trying to improve a single energy system and not affect the rest at all through isolated enzymatic activity doesn't really work too well. In this case, some, but probably not to a measure that would produce statistical significance in a good portion of the literature.
What it actually comes down to is this. More so than the actual use
of phosphocreatine as energy, there was that not-quite-fantastic-but-certainly-detectable increase in the stores. Phosphocreatine is protein and as a general rule, where protein goes, water follows. In this case, quite a bit of water. You know about this part, right? When you take creatine, your muscle totally fills up with water. You've experienced this before, yes?
This makes your muscle larger. And it's larger in a way that's not damaging like NO-2's effects. Overall increases in muscle cross sectional area are generally attributed heavily to increased storage of water, carbohydrates, and protein within the muscle. It's not as much the actual increase in the girth of the muscle fibers. And you could make the argument that increased cross sectional area is equivalent to increased strength, but there are so many tricky components here that it isn't worth discussing.
Realistically, a decent portion of the strength gain is a psychological effect. Physiological reasons certainly exist for creatine's effectiveness, but those alone won't account for the entirety of the effect size. Creatine is a little more potent than what you can attribute to the creatine phosphate energy system changes. And that's the psychological component I'm talking about.
You have slight energy cycle improvement and totally
hydrated muscle that's obviously now larger, and feels pretty nice. Your central nervous system enjoys your niceness feeling and picks up the tab from there and makes it physiological. Your muscle is way stronger than you think. A sedentary mother can lift a car off a child. That's the power of the central nervous system allowing her body to recruit more of her muscle than she would be otherwise capable of. When your muscles are larger and feel fantastic, you get a similar effect. Especially when you're nudged in the right direction from slight strength increases related to your energy cycles. Not quite car-off-a-kid strength, but I would be surprised if you didn't add a rep or two to lift here and there.
Granted it's not steroids. But for a safe and natural sports supplement, so far creatine is as good as it gets. So yes, creatine has my approval. Feel free to take it. 20 grams per day, every day, for a month. Any more than 20 grams and there's absolutely no way you'll see further increases in phosphocreatine stores. It would be 100% pee. Longer than a month and it's just wasting your money. Creatine's not free. Split it up into a few servings as to not ingest all 20 grams in a single sitting. And especially take it before workouts. And insulin helps. Insulin is a hormone that has tons of functions, but one is to really encourage energy substrate storage. Carbs, protein, and fat are all affected by this. Phosphocreatine is a protein. Insulin encourages it to be stored in the muscle to a greater extent. Taking sugar with the creatine keeps a little more of it out of your pee. And drink tons of water. You need to. Good?
Plus, if you happen to live in the UK, buy it from myprotein.co.uk. I like these people. For whatever reason, everyone in the UK has tried to buy my domain name off me, and the only group that wasn't completely mindless and offensive to talk to was them. Only one. And not only that, but they were actually pleasant and complimenting. Thus, I hope they do well in life. So if you're a UK person, buy your creatine from them. I'm pretty sure they'll be super nice to you too.