Most of them came from playing football.
Tappin, who helped Flintridge Prep win the CIF Southern Section Division XIII championship in 2003 against Prep League-rival Pasadena Poly as a linebacker, reached his final decision last summer to walk away from football after consulting with doctors following a linebacking drill at a Washington University preseason practice led to a dizzy spell.
"I felt dizzy and took my helmet off," said Tappin, who is majoring in history and economics at the Division III university. "The team training staff and a neurologist at the university's hospital diagnosed me with a concussion.
"I went through a battery of tests and decided it was best to not play football. It was a tough decision, but when it came down to it, it was about me going to class."
Tappin, a former All-Area first-team selection in football, wasn't going to give up athletics.
The sophomore had a back-up plan. He chose to compete on the university's track and field team, which is piloted by Coach Paul Thornton.
Tappin, who won the Prep League titles in the 200-meter and high jump events in 2005 at Claremont-McKenna College, was a sprinter and jumper and competed in the decathlon for the Bears last year.
"I felt fortunate that I could do another sport," Tappin said.
CHARLES RICH covers sports. He can be reached at (818) 637-3228 or by e-mail at charles.rich@latimes.com.