Promoted to Front Page by T.P. Grant -- Photo by Esther Lin of MMA Fighting

Power is a difficult thing to define. Some fighters clearly have it: no one would dispute that Junior dos Santos hits really, really hard, for example. Some fighters clearly don't: only the most deluded fan would cling to the notion that Frankie Edgar is a power puncher. I've been trying for some time to come up with an objective way of measuring and comparing power, and I've finally found it.

On the mobile version (though not the computer version) of the FightMetric website, they've included a new statistic: knockdown rate. It's exactly what it sounds like - the number of knockdowns a fighter averages over fifteen minutes of fighting - and it's a useful statistic in and of itself. A knockdown, hopefully leading to a knockout, is the ultimate expression of a fighter's power. I wanted to go a step further, so I multiplied a fighter's strikes landed per minute rate by fifteen, and then divided it by the knockdown rate to quantify how likely an individual strike is to cause a knockdown. The lower the number, the more powerful the striker.

This has the benefit of controlling for some fighters who achieve knockdowns by massive volume striking, or others whose power is obscured by throwing for an extremely low volume. Additionally, it controls for fighters who tend to finish extremely quickly, which can obscure the general pattern. Obviously, some things get lost here: FightMetric's significant strike statistic also includes powerful ground strikes, which by definition cannot cause a knockdown, though this is less of a problem than it seems since FightMetric is extremely conservative about classifying ground strikes as significant. It also makes no distinction between power punches, jabs, knees, head kicks, and leg kicks. These different types of strikes are not all equally likely to cause a knockdown, though one could point to at least one occasion on which each has. I would argue, however, that the result - a knockdown - matters a great deal more than the specific type of strike.

(A note to those who automatically distrust FightMetric statistics: no, they're not perfect, but we can at least expect their analyses to be internally consistent. If the whole system is flawed, then so be it, but for large-scale analyses of many different fighters the comparative data are useful.)

Some of the results from this statistical analysis are unsurprising. Yes, Junior hits hard, and the statistic confirms it; Frankie doesn't, and the statistic also confirms that. In the middle, however, the results are quite interesting. We can now say, with relative certainty, that certain fighters' power has been massively overrated by pundits and highlight reels, while others don't get nearly enough respect for their ability to put an opponent to sleep. This statistic also allows us to say, once and for all, that power isn't solely the product of swinging like a drunken brawler: timing and accuracy matter just as much, as the leaderboard makes clear. Of course, throwing ridiculously hard punches helps, but that's not the sole, or even main, component of power.

Let's start with the leaders in the clubhouse. Some names will be surprising, and some won't.

Notes: Erick Silva would sit atop this list, with a rate of 22.02, but the sample size is only three fights. Others I've excluded are Drew McFedries (18.02) and James Irvin (19.65), given the fact that neither has fought in a major organization in more than two years and both seem unlikely to make a return in the near future.

So what's noteworthy here? First, this metric seems pretty neutral as far as weight classes are concerned. Every division except for featherweight and flyweight boasts a representative on the list, and there's only one heavyweight in the top five. Featherweight doesn't really have many power strikers in the top 25: the highest entrants, by this metric, were Jose Aldo (59.83) and Erik Koch (58.45), while flyweight doesn't have enough fighters, period, to really do much analysis. Second, middleweight is the best-represented weight class: I honestly have no idea why this is the case, none at all. Any suggestions? Third, Luke Rockhold might be the most surprising name on this list: while I'm a fan of his, I'd never really thought of him as a fighter with outstanding power, yet here he is.

Finally, and most important, almost everyone on this list can be classified as a technically proficient striker, at least offensively. Good technique, whether it's boxing, Muay Thai, kickboxing, or something more exotic, tends to produce results. Additionally, they're almost all older than average (31.22 years). I think that's a product of several factors. First, older guys tend to be stronger: the longer you've been putting your body through physically demanding tasks, the stronger you get, up to the point when your body physically breaks down and your testosterone levels start to seriously decline. Second, and far more important, older guys have had substantially more time (thousands of hours more, in the aggregate) to learn the intricacies of striking. Footwork, accuracy, and timing, while to a certain extent innate, can be greatly improved by additional time in the gym, and these three things are just as important to producing power as swinging really hard. This has always been my theory on Anderson, for what it's worth. He's just spent so much more time striking than everyone he fights that it's no wonder he makes them look like novices: compared to him, they really are.

With that said, how do the younger fighters on the list fit with this idea of training time? Ellenberger, Daley, and Guillard are relatively young (27, 29, and 29), but have already been fighting for a long time, and all got into the game at a young age. Ellenberger has been fighting for seven years, Daley for nine (with a background in karate and Muay Thai before MMA), and Guillard for nearly ten years. In each of those cases, it's easy to point to their explosiveness as the major component of their power, but all three have surprisingly technical offensive arsenals. What about Gustafsson? While he's only been fighting for five years, and is barely 25, he started boxing at age ten. Pettis? He had his first MMA fight on his twentieth birthday, but had a background in Taekwondo and kickboxing before that. Michael McDonald might appear to be a major exception, given the fact that he's barely old enough to order a beer, but he's already been fighting for five years and started kickboxing at age ten.

There are, of course, some outliers. Carwin has never struck me as a particularly technical striker, but his physical strength is indescribable. Stann isn't particularly old (31), and hasn't been in the game for a long stretch, but he's an exceptional athlete, and perhaps the Marine Corps' striking instruction is more intensive than I'd thought - from what I'd understood, the Marine Corps Martial Arts Program (MCMAP) focuses mostly on grappling.

Let's move on to the overrated category. Who are the guys who are commonly thought to have power, but really don't?

Who would've thought that Chris Leben hits about as hard as Carlos Condit, or that Josh Koscheck has more in common with Alan Belcher than Dan Henderson (55.15)? Highlight reels are a wonderful thing, but they don't tell the whole story; in fact, they often serve to obfuscate more important trends. This doesn't mean that fighters like Koscheck or Evans are incapable of knocking their opponent out, but that they're not particularly likely to do so. Derek Jeter and Alex Rodriguez are both perfectly capable of hitting home runs, but one is substantially more prone to it than the other.

This statistic should also serve to temper our expectations of certain fighters. When viewed as an aggregate whole, GSP's ability to knock opponents out depends almost entirely on landing a flush high kick. Throwing overhands, as he did against Shields, is basically counterproductive: sure, he could get lucky and land one, but the fact that something could happen doesn't mean it's likely, nor that you should base a game plan around it. On that note, wrestlers who headhunt are my biggest pet peeve about MMA striking, and the data bear this out: despite throwing power punches almost exclusively, most of these former wrestlers don't show any particular tendency toward serious knockout power. Evans, Koscheck, Faber, Maynard (the Edgar fights aside) and Munoz are extremely unlikely to successfully land a fight-ending strike, yet they consistently go out and fight to do precisely that. There are, of course, exceptions to that rule: Dan Henderson (55.15), Ryan Bader (47.81), Johny Hendricks (48.6) are all serious threats to put just about anybody down.

So this is what we've learned from strikes landed/knockdown. It's a massive improvement over the simple knockdown rate, according to which Vitor Belfort would be on the same level as Martin Kampmann or Anthony Njokuani. Statistics don't tell the whole story, but they're a meaningful accompaniment to impressionistic anecdotes, even if they don't capture the beauty of one of Anderson's vicious clinch knees, Junior's uppercuts, or a Cro Cop high kick.