"We've been working on his strength," Swenson coach Tim Hickey said. "He didn't like running the quarter [400 meters] before, but he's finally buying into the fact that if you run the quarter well, it helps you run the 200 better."
His early success has translated into a sizable momentum three weeks into the outdoor season.
In his first event of the season, at the Pennsylvania Track Classic on March 30 at Plymouth Whitemarsh, Mathis coasted to victory in the 200 in 21.72 seconds, breaking the 28-year-old meet record of 21.84 set by Central's William Reed in 1985.
Showing his enhanced strength, he went on to win the 400 only a few minutes later.
Mathis then continued his hot stretch at the Haverford Invitational on Saturday, as he defeated fellow state champion Wellington Zaza to win gold in the 100 by more than a half-second in 10.69. He went on to win the 200, too, with Zaza finishing close behind in second.
"This year, he's the man," Hickey said. "Last year, he wasn't quite at the level he is now, but this year, he knows he's the guy."
While the last two years have been good to Mathis, the road hasn't always been easy.
During his freshman year at Fels, he skipped most of his classes and didn't put effort into his work. When his family saw him veering off onto the wrong path, they moved him to Swenson.
"I knew they had a good program at Swenson, and I knew that it was something good for me," Mathis said. "But academic-wise, it changed a lot, too. Because Swenson is a smaller school, it was easier to concentrate in the classroom, and I'm just more focused."
He was also suffered a personal setback in 2010 with the death of his grandmother, who had played a major role in his life.
A large tattoo - with the words "RIP Linda" and the dates of her birth and death - adorns his upper right arm.
"She enjoyed watching me compete and run," Mathis said. "Every time I step on the track to race, I run to my best ability because I know she is looking down on me smiling, and I'm making her proud."
Because of his rough start to high school, the final months of his senior year will play a crucial role in whether he competes at the next level.
Mathis has received interest from a number of Division I schools, including his top choice, Coppin State.
He plans to take his final SAT in May and then make his decision based on scholarship offers.
While he faces an unavoidable amount of pressure to succeed both on and off the track, Mathis has had no trouble staying focused on the ultimate goal of his high school track career.
"I want to win nationals," he said. "I just want to win in something - whether it's the 100, 200, or 400. I just really want to win nationals."
Contact Austin Odenbrett at email@example.com. Follow on Twitter @austinodenbrett.