Thus a defensive end was born. More than a decade later, it seems to have worked out.
"Once I started playing there, it was a comfortable fit," said McAdoo, a 6-foot-7, 228-pound member of the Tar Heels' 2008 signing class.
"When I was little, I always used to run with the skill guys -- the running backs and receivers. I got it through my head if I could beat them, I could beat an offensive lineman."
The combination of size and speed made McAdoo a three-star prospect, according to most recruiting services, and caught the attention of North Carolina's coaching staff. He was a welcomed addition to Butch Davis's latest signing class when he selected North Carolina over Kentucky a week before National Signing Day.
McAdoo recorded 48 tackles (19 for loss), six sacks, three forced fumbles and an interception as a senior while being named one of three finalists for Tennessee's Class 5A Mr. Football Lineman of the Year award. He was also a productive pass-catching tight end.
The bulk of McAdoo's defensive stats come against double-teams or with opponents running away from him.
"It was a little frustrating, because all I was thinking about was stats and how I could help my team," McAdoo said. "But the double-teams this year helped me get better and work on getting through it. Nine out of 10 times, if you're double-teamed in high school, you're going to have to go through a double-team in college."
McAdoo's talent spoke for itself in three seasons as a varsity player at Antioch High School. His dedication in the weight room is more visible now than ever. He lifts twice a day, five days a week.
Away from the field and basketball court, where McAdoo recently helped the Bears reach the Class AAA state basketball tournament as a center averaging 11.7 points and 6.4 rebounds, the passionate athlete prefers the role of a reserved teenager.
The soft-spoken, deep-voiced McAdoo does not put himself out there for everyone to know and understand. But he has a plan in mind for his future, and it involves success at Chapel Hill.
"I got it mapped out," McAdoo said. "I'll go to summer school and stay until football starts, work hard and try to put on weight. My goal is to reach 235 and I'm 228 right now. I want to get comfortable with North Carolina and how they want me to play. I want to start, but if I redshirt it wouldn't hurt a lot. I'll just have to work hard in practice for four years, or however many it takes to go to the next level.
"I never get too happy or stuck on myself because I'm a guy that stays humble. I take it as everything happens for a reason. If I'm lucky, I'll be playing in five years on Monday Night Football. If I keep my steps straight and my nose clean, I'll be OK."
McAdoo has been a pretty capable forecaster so far. His eyes were opened to playing college football as a high school sophomore when recruiters came to see then-Antioch running back Preston Brown (currently at Arkansas State), and McAdoo realized he could benefit just as easily as his teammate.
More recruiters spread the word about McAdoo the following season when they came to see fellow defensive end Jeremy Buchanan, who signed with Tennessee-Martin.
"When they came to see them," McAdoo said, "they had to see me."
McAdoo lists Julius Peppers, another 6-7 North Carolina product, and 6-4 Jevon Kearse as defensive ends he has modeled his style after -- tall, physical pass rushers with a fast first step.
It's a style that Davis and defensive line coach John Blake, who recruited McAdoo, should be able to make use of in the coming years.
"The reason I picked North Carolina is because of Coach Blake and Coach Davis," McAdoo said. "The one thing Coach Blake told me is he doesn't teach everybody the same way. He can't teach a 6-7 guy what a 6-1 guy would do. With my wingspan, if he can teach me good hand techniques … I'll be good."
Jeff Lockridge covers high school sports at The Tennessean and has reported on McAdoo for the duration of his high school career.