The UFC Arms Race & the Incredible Shrinking Middleweight


[This feature is an abridged excerpt from Chapter 6 of the book, “Fightnomics.”]

In 2005 Kenny Florian made his Octagon debut at the finale of the inaugural season of The Ultimate Fighter. Weighing in at 183 pounds and competing at middleweight, Florian went on to suffer his first (and only) TKO loss at the hands of Diego Sanchez. Then Florian went on a diet, returning to the Octagon later that year 15 pounds lighter as a welterweight, and rattling off two quick stoppage victories. But Florian wasn’t done shrinking. In 2006 he dropped another 15 pounds for his lightweight debut. He would stay in that division for four years, amassing an impressive 9-3 record, with his only losses coming in title fights or title eliminators.

In 2011, with the lightweight title picture clogged by the Maynard-Edgar battles, Florian tightened his belt by 10 more pounds and moved down to featherweight, now weighing in 40 pounds lighter than in his UFC debut six years prior. When he retired two fights later, the Florian was the only fighter to have competed in four different UFC divisions. Florian was an extreme case of a subtle underlying trend in the UFC. To let’s take a step back and ask ourselves: how often do fighters switch weight classes, and how has the average size within a division changed over time?

Analysis of UFC fighters from 2002 to 2013 with at least two Octagon appearances found that 38% of them had competed in at least two different weight classes. If we filter down to fighters with at least four appearances, then the metric leaps to 56%. That means more than half of all UFC fighters will drop a division if they compete for at least four fights. Size is an advantage in MMA, and the overall trend in the UFC is for fighters to get better at managing their weight and compete in lower divisions. When a fighter moves down a division, he is suddenly facing smaller opponents. There’s a cost to this weight cutting, but on fight night the payoff remains. It turns out that fighters dropping a weight class will win 55% of their debut fights in the smaller division, a macro advantage similar in magnitude to other Tale of the Tape advantages. Bold moves that seize advantages are rewarded, while those who persist in a disadvantaged state get punished harshly. Regardless of whether a fighter moves down a division to gain a size advantage over future opponents, or is forced down due to an existing disadvantage against his current division’s opponents, the net improvement appears to be worth the move for the majority of UFC fighters today.

Competition is a powerful force, and MMA perhaps more than any other sport is an unforgiving cauldron of competition. Skills get put to the test, conditioning gets pushed to extremes, and any hole in a fighter’s game will get tested and exposed. The UFC has evolved rapidly under these pressures. Today’s top MMA athletes are full-time fighters with cutting edge training camps. They have nutritionists and supplement sponsors. During fight week, they may even have a personal chef to travel with them to help manage the weight cut and rebound. All of this means that the amount of raw athlete packed into each pound that steps on the UFC scale at weigh-in time is as at an all-time high, and could even go higher.

If these trends are real and all the emphasis on size management is working, then we can assume that fighters in prior years may not have been optimizing their size as well as fighters do today. With the right analysis, we should be able to see evidence of that. Here’s how average fighter size (height and reach) by division has changed over the last decade.

The graph shows that the average size of each legacy UFC division (that existed before Zuffa’s addition of the WEC) has grown in average height and reach over time. I’ve used a weighted average that simply looks at any fighter appearance in the Octagon by weight class and captures the height and reach. The reality isn’t just that modern fighters are taller and longer than fighters a decade ago, it’s also that the very same fighters weigh less than they once did. Fighters have shrunk their waistlines, while divisions have sprouted vertically and horizontally – all thanks to the perpetual arms race that motivates athletes to become champions.

In smaller weight classes where the weight cut to drop a division is also smaller, we see larger relative changes in size. Lightweights didn’t even have a division they could move down to until the WEC merger in 2011, so plenty of fighters who could have competed below lightweight were hanging out in a larger division simply because it was their only opportunity to compete in the UFC. While my analysis used larger sample sizes to ensure the hypothesis was well tested, I’ve also isolated the same size values for even more recent periods like 2011-2013, or just 2012-2013. It seems the divisions aren’t done growing. The more recent the period of data I use, the larger the legacy divisions get. It’s an arms race, and it’s not over yet.

Let’s return to the case of Kenny Florian, who migrated 40 pounds and four weight classes down the UFC divisions with the same-sized frame that was five foot, ten inches tall with a reach of 74 inches. According to the chart, he was a tiny middleweight, but a fair-sized welterweight. At lightweight, however, Florian had a size advantage over the average division opponent, so it’s no surprise that he found a home in this division for most of his career. When Florian cut down to the next division, he was huge by comparison. He had a big size advantage over most featherweights who averaged five foot eight with a reach of only 70 inches.

As a first step to understanding the relative importance of basic anthropometric differentials in MMA, we see that competitive dynamics strongly suggest that size does matter. However, there’s much more explore on how exactly size matters, and how it doesn’t. Now retired from fighting, but having clued us into an important competitive trend in MMA, I wish Kenny many satisfying meals at all-you-can-eat buffets.

“Fightnomics” the book is now available on Amazon!

See the Book page of this website for the latest links to different versions the book, and follow along on Twitter for the latest stats and analysis.



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