CARLSBAD, Calif. — Mike Evans, a former star receiver at Texas A&M, crouched in a three-point stance in shorts and a T-shirt and then bolted down a soccer field as a high-speed camera recorded every step. Evans was here not to catch footballs or to practice dodging defenders, but to hone his technique for the 40-yard dash.

Ahead of the N.F.L.’s scouting combine, with workouts set to begin Saturday, Evans and about 20 other top college football prospects arrived most mornings at a picturesque field in Southern California to learn the art of sprinting from Ryan Flaherty, a strength and conditioning coach whose specialty is speed.

Held in Indianapolis every February, the four-day combine is part job fair, part track and field meet, with team interviews and a gantlet of physical tests. There are no medals handed out, but the athletes who run the fastest and jump the highest can expect their stocks to rise as the N.F.L. draft approaches in May.

For many players entering the draft, the 40-yard dash, one of the highlights of the televised event, will be the most important sprint of their young lives. So every year, players like Evans, 20, prepare by arriving for a two-month combine boot camp, hoping to shave tenths of a second off their times.