"I run so I don't waste the gift I was given," says Coby Jacobus, "which is a second chance."
The running coach at Manchester Central High School in New Hampshire is referring to returning to the sport he loves after discovering he needed a kidney transplant as a senior in college.
"Running was one of those things I could always turn to," he says in the video above, the latest in a web series from DICK'S Sporting Goods about why runners do what they do. Suddenly, he was too sick to do what he loved.
He has his father to thank, he says, for introducing him to running and fostering his love of the sport. His father also donated one of his own kidneys when Jacobus fell sick.
Since then, in addition to coaching a group of resilient and driven high schoolers, Jacobus has run a 2:40 marathon, an 18-mile race covering 9,000 feet of elevation gain and more -- and yet still wonders how much better he could have been.
Watch the video above for more from Clark, then tell us in the comments why you run.