A ‘high butt factor’ might be an NFL Draft prospect’s most prized asset

“So you want me to comment about how important a guy’s ass is in the evaluation?” Mike Mayock asked, laughing. “You’re really doing this, huh?”

For years, the humble human haunches have been key indicators for football scouts as they evaluated players. Mayock, the former Las Vegas Raiders general manager, has reluctantly been installed as leader of the Cult of the Caboose since referencing the rump multiple times as an NFL Network draft analyst in the 2010s, which makes him a great source for a story about seats.

“Over the years on television, I used to call it a power generator, and really, it was to be a little cute and funny with a germ of truth. It just kind of became representative of a strong lower body,” Mayock said. Sure enough, YouTube is full of clips in which Mayock references a player’s “bubble” butt.

“I said it on the air at the combine multiple times to the point that it was almost embarrassing because our cameramen would be getting shots of the guy from behind to illustrate it,” Mayock said.

At least he’s in good company. Six-time Super Bowl-winning head coach Bill Belichick is a fellow devotee of the derriere, according to Georgia coach Kirby Smart. In a video posted to X last year, Smart described the time he joined Belichick to watch defensive linemen run the 40-yard dash at the NFL combine. Smart, then the Dolphins defensive coordinator, was confused by Belichick watching the drill from behind the starting line.

“I was like, ‘Why are we here? You can’t time the finish,’” Smart said. Dolphins coach Nick Saban, a friend and former colleague of Belichick’s, had the answer, according to Smart: “Bill likes to look and see how big their ass is when they get down in a 40-yard stance because he wants to sign the biggest-assed defensive linemen he can sign.”

There is science behind this slightly cringy bit of scouting, the “germ of truth” Mayock mentioned.

“In a broad sense, muscle hypertrophy (size) relates to muscle strength,” said Dr. Alexandra DeJong Lempke, an assistant professor at Virginia Commonwealth University’s Department of Physical Medicine and Rehabilitation. “Usually a larger muscle indicates higher ability to produce force. So when you think of sprinting and explosive movements, that’s primarily driven from the glute maximus to give that explosive first step.”

Football coaches have known this inherently for years even if they can’t break it down like a Ph.D.

“It’s one of the largest muscle groups. It’s a prime mover of your hips. It’s what propels you forward. It’s what puts force in the ground,” said Luke Day, head strength coach at the University of South Carolina. “You know that player has the potential to create a lot of power because that muscle group is that important.”

The first time Day learned there was a correlation between asses and athleticism came at a football camp at Miami (Ohio) University with strength coach Dan Dalrymple, now the Denver Broncos head strength coach. “Literally the first thing (Dalrymple) said, he said, ‘You guys come in here and you got a flat can, then we don’t want you,’” Day said. “I heard that as a 13-year-old so I wanted to make sure I squatted so I had a big ol’ butt.”

Day has never quit working in the weight room, and he’s never quit believing in the power of the posterior. “It is an attribute of athleticism,” he said. “The more people on your team that have one, the better.”

“The biggest lever you’ve got on your body is your hip, so the biggest power angle you have is from the knee to waist,” Atlanta Falcons offensive line coach Dwayne Ledford said. “Football is all about power angles.”

Ledford is reminded about the power of the posterior at both work and home. When he was the offensive line coach at N.C. State, Wolfpack strength coach Tim Rabas commented on the physique of Ledford’s then-4-year-old son, Hudson. “He’s like, ‘Led, that dude is going to be strong.’ I’m like, ‘What are you talking about?’ He’s like, ‘Look at his posterior chain. That dude’s got a back on him,’” Ledford said. “Even now my wife and I joke about it. ‘Look at that posterior chain, man.’”

Turns out Rabas, now an assistant in the Carolina Panthers’ human performance department, may have been on to something.

“(Hudson) has got power,” Ledford said. “He’s about to be 11, and he gives me everything I want wrestling with him.”

So, yes, asses are important to coaches. Which means they are important to scouts, who have been checking out butts as long as football players have had them.

“When I was a young kid and got into scouting, I heard the term ‘anchor.’ I was like, what is anchor? It’s a big ass,” Falcons assistant GM Kyle Smith said. “One of the first things you learn getting into scouting is the anchor. Big asses, big rear ends, posterior chain — back and ass and hamstrings — that’s how you anchor.”

Old-school scouts would cross linemen off their list after just seeing them walk down a hallway, Smith said. “You see a guy walk by and you say, ‘Can’t anchor. Don’t need to watch any tape.’”

It’s not just on the line of scrimmage. The Caboose Correlation is used as an athletic indicator at all positions. Former NFL punter Dustin Colquitt said the talking points at his end-of-season exit interviews with Kansas City head coach Andy Reid were generally pretty uneventful, except for one.

“He’d sit down with me and be like, ‘You went to the Pro Bowl, and we don’t have much to say to you. But don’t lose your butt. Punters have to have big butts. As soon as you start to look like you’re going downhill from a physique standpoint, you’re out of here. Keep that ass going.’”

The rear end’s importance is so front of mind for NFL scouts and coaches that they’ve come up with their own language to reference it.

“We used to call it the ‘Seat of Power,’” said former Washington Commanders and Cincinnati Bengals head strength coach Chip Morton, now the senior associate director of strength and conditioning at South Carolina.

There are plenty of other rump-related euphemisms. Three NFL general managers with scouting backgrounds laughingly confirmed the link between butts and brawn at the combine in Indianapolis, but all three declined to discuss the subject on the record. One did say he’d heard it called a “woodhauler’s ass” and then mimicked — in the middle of a crowded Starbucks at the JW Marriott — how carrying a large load of firewood might build a person’s glutes.

When Pat Kirwan was scouting for the Buccaneers and Cardinals in the 1980s, scouts labeled prospects with a “high butt factor” and noted it on all written scouting reports.

“We always abbreviate everything, so on a scouting report it would just be ‘HBF plus 9’ or ‘plus 10,’” said Kirwan, who went on to coach and work in personnel for the New York Jets and now hosts an NFL radio show for SiriusXM. “We’d give them a numerical grade on it.”

Clemson defensive lineman Tyler Davis remembers a former Tigers assistant coach telling a teammate he had “a Coca-Cola booty.” He didn’t understand the soft drink reference.

“We had all types of buzzwords at Clemson that were thrown around,” Tigers running back Will Shipley said (his favorite is “bully back”). “Around the football environment, it’s just something people look for, especially for the explosive athletes.”

There is also phrasing for the opposite end of the spectrum. If a coach is calling a player “light in the ass,” that player knows his time on the team might be short.

“I had a tackle who was light in the ass,” Kirwin said. “As soon as the defensive guys saw that, they were bull-rushing him. They knew he couldn’t drop his weight and stop a bull rush. They can figure out pretty quick who they are going to whip up on.”

A player taking what coaches and scouts call “NoAssAtAll” pills has got work to do in the weight room, said The Athletic’s Nate Tice, a former college football player and NFL staffer. When Senior Bowl executive director Jim Nagy was scouting college games for the Kansas City Chiefs and Seattle Seahawks, he’d simply write “saggy pants” if he was worried about an offensive lineman’s anchoring ability.

“You occasionally get an exception, but if you’ve got a guy with a big, ol’ bubble butt and he squats the house or has crazy acceleration or a great vertical or broad jump, you never wonder why,” Day said. “If you’ve got a guy getting moved around or tossed out of the saloon and he’s flat — ain’t got nothing behind him — that’s the first thing that comes to mind.”

For college coaches, the development of the derriere can be especially important for indicating which high school players will bulk up as they age. They take it as a matter of faith that a player’s body will catch up to his butt.

“It sounds weird, but I’ll go to these recruiting functions, and I’ll bring my wife and I’ll go, ‘Did you see his butt?’” Day said. “I’m all excited about it, and she’s like, ‘What are you talking about, you weirdo?’”

At the NFL combine in February, Shrine Bowl scout Owen Riese predicted Texas Tech safety Tyler Owens would post great athletic testing numbers the next day.

“You’ll notice he’s well-endowed in the posterior,” Riese said. “Typically guys who are more explosive are more well-endowed in the rear. There are some guys who are going to have a tough time finding pants, like, ‘I’ve got a 34 waist, but I really need to wear 40 because otherwise they don’t fit around my butt.’”

The next day, Owens came within one inch of breaking the world record in the broad jump by leaping 12 feet, two inches from a standing start. His overall athletic score of 89 set by Next Gen Stats marked him as the most athletic safety in this year’s draft class.

Owens came to the combine unaware so many scouts would be checking out his tush. “I guess (that’s why) they have us in those little compression shorts,” he said. “They want to see if you’re toned up and cut up.”

South Carolina wide receiver Xavier Legette, who ran a 4.39-second 40-yard dash and posted a 40-inch vertical at the combine, has steadily risen up draft boards since the end of his collegiate season even in a crowded field of wideouts.

“Wait till you see that beeee-hind,” Day said.

This year’s most glute-gifted prospect is Texas defensive lineman Byron Murphy “whose ass and legs are tree trunks,” according to Shrine Bowl director of football operations Eric Galko.

“You think, that kind of looks like Aaron Donald looked,” Galko said. “It’s a hugely predictive measure. A lot of teams are measuring it now, whether it’s through biomechanics or an actual tape measure, just to make sure they have an idea of what your potential is as an athlete.”

In fact, the butt can even be a measure of the heart.

“It’s a reflection of not only their strength but also it shows, ‘Does this guy care?’” Galko said. “I don’t know if there is a direct correlation between how much you squat and how much you care about your lower body and success in the NFL, but I bet you there’s some correlation between having a strong lower half and being somebody who works their ass off in the weight room.

“No pun intended.”

(Illustration: Eamonn Dalton / The Athletic; photos: Justin Casterline, Kevin Sabitus / Getty Images)