Psychologists could spend years analyzing the make-up of a fullback, but Oklahoma offensive coordinator Kevin Wilson believes they would all find a common trait among the good ones.

“You have to be a little bit demented,” he said.

Matt Clapp doesn’t complain about dementia — at least not yet. But even he admits the position he plays takes a mindset that isn’t for the faint of heart.

“All your plays are just head-on collisions, all the time,” Clapp said. “I find it fun. It’s a lot of fun.”

Aside from, perhaps, deep snapper, fullback is the least glamorous position on a college football team. Offensive linemen may just block, but at least five spots are reserved on all-conference and All-American teams. The NFL still throws loads of money at those who can open a crease for a running back and keep a quarterback upright long enough for a receiver to get open.

Fullbacks don’t have those luxuries.

NFL teams rarely keep more than one on a roster and pay bottom dollar to the good ones. As far as college accolades go, there’s little to go around.

Clapp knew all this when he was recruited out of Phoenix’s Paradise Valley High School. Clapp was a fullback during his prep career, but who that carried the ball more than he blocked. He rushed for over 1,000 yards and scored 18 touchdowns his senior season. But he knew that would change when he decided to attend OU.

“They didn’t tell me that, but I kind of got the clue on my own,” he said. “I knew I would probably catch a ball here or there, but that would probably be it. My big plays are blocking plays.”

Clapp is the rare exception in that he actually came into the position with past experience as a running back. Most were either high school tight ends or linebackers.

Wilson said there’s a reason for that. Playing fullback takes a mindset that calls for collisions that human instinct and society norms say to avoid.

“You walk down a hallway and you’re about to run into somebody, you stop and say excuse me,” Wilson said. “For them, blocking is running through things. When you hit a wall, you stop. When you block, you hit and keep running. It’s a completely different mindset. It takes a completely different human being. It’s not a toughness as much as a body that can hold up to it.”

Clapp’s body can. He’s 6-foot-3 and 234 pounds.

However, Wilson jokes the average fullback will shrink several inches throughout his playing career.

“There’s a compacting,” he said.