Your weight class kind of doesn't matter until black belt, if you're above feather weight
A deeper data-driven amendment because Reddit got mad at me
In last week’s story, I made kind of a bold postulate: Among colored belts, one weight class didn’t seem to make a difference in 3,000 IBJJF open class matches. And to be fair, when we looked at the data in aggregate, this appeared true. The lighter of blue and purple belts were winning 51 and 49 percent of those matches respectively, and there was no linear relationship between weight class differences and win rate among blue, purple, and brown belts.
However, dissenters brought up a good point: One weight class means a lot more to a rooster weight than a heavy weight. For men, rooster to light feather is 14.6 lbs, or an 11 percent jump in body weight, while heavy to super heavy is a similar 14 lbs, but only a 6.7 percent jump in body weight.
So, I broke everything down into weight class head-to-heads. If you like matrices, get your snacks ready 🍿
Looking at female colored belts (blue, purple, brown) overall, we can see light feather and feather athletes still really struggle in the open class. However, light weight and heavier athletes see an almost an even playing field, with any combination of light, middle, medium heavy, and heavy weights seeing a 45 to 50 percent success rate. Heavy weights beat super heavy weights (anyone over 175 lbs, no weight limit) six out of ten times.
Male colored belts see a similar pattern, where light feather and feather athletes have limited success in the open class. Light weights start triumphing against middleweights and super heavies. Maybe the story of the colored belt guys is the medium heavies, who have had a slight upper hand against all three heavier weight classes. Like the women, the second-to-last weight class before there’s no limit, super heavy, beats the no-limit weight class, ultra heavy, more than half the time.
Black belt is a totally different story. We don’t have enough recorded matches among even feather weight black belt women to say much about them. Like previous aggregate data showed, even one weight class mattered a lot. Five out of 13 light weight v. super heavy weight matches went the way of the light weight.
Among black belt men, more feather weights braved the open class but didn’t see a lot of success either. The relationship between weight and success was much more linear. The only combinations of classes where the lighter athlete won more often were medium heavy v. super heavy, heavy v. super heavy, and super heavy v. ultra heavy.
Also, maybe obvious take away: rooster weights didn’t enter enough open class matches to be able to make any calculations about them. Across all male and female belts and weight combos, roosters won three out of 45 open class matches in our data. As much as we want to be champions of Mikey Musumeci v. Seif Eddine Houmine, it just seems statistically unlikely.
About the data
Match data was collected by IBJJFRankings.com (@ibjjfrankings on Instagram), an initiative to establish ELO rankings for IBJJF athletes. Win percentages per weight class head-to-head were not calculated when there were fewer than ten matches, which are denoted by “N/A” in the tables.