Now he's a full-time runner with a 2:13:55 personal best, putting in 160- and 170-mile weeks. He's the bright young hope of U.S. runners in Monday's 105th Boston Marathon.
To Cox, 25, there's one reason for his transformation at 26.2 miles. He joined a training program for U.S. runners initiated by the Italian shoe company Fila and designed by Gabriele Rosa, who coaches several of the world's best distance runners, including two-time Boston champion and Monday entrant Moses Tanui of Kenya.
Cox underwent physiological testing last spring and was accepted into the program, which now has 11 runners. He began training with the group in August outside his hometown of San Diego.
He quit his job making virtual business cards on CD-ROMs, moved out of the pool house at his father's home and joined other Fila runners in Alpine Village, Calif. He gets meals, massages, travel expenses and a stipend.
''Being able to just focus on training and getting ready for the next run has made the difference and allowed me to make the jump I did,'' Cox says. ''There's no way I could run 170 miles a week with a job.''
Ten weeks after joining Rosa's group, Cox ran a breakthrough 2:13:55 to finish 10th in October's Chicago Marathon.
''I think I'm definitely more fit coming into this race than going into Chicago,'' Cox says. ''It's hard to predict times. If I was going to a flat course like Chicago or Rotterdam, I definitely feel I'm 2 or 3 minutes faster.''
Cox trained from Jan. 15 to Feb. 15 in Kenya, staying at Tanui's home in Eldoret while running with dozens of top Kenyans two or three times a day.
''The whole experience was incredible, a real eye-opener,'' says Cox, whose long-range goal is the 2004 Olympic team.
''Just to see their work ethic, see that running is their passion, their lifestyle," Cox said. "Having someone like Moses, who's been at the top of his sport for so long, tell me things don't happen overnight in distance running.''
Returning to San Diego, Cox has been emphasizing downhill running to prepare for Boston, a hilly course with a net drop in elevation from start to finish. He recently completed a 35-kilometer (21.7 miles) run 10 minutes faster than he did before Chicago.
In March he did a practice marathon in 2:21:46, and three days later paced the Los Angeles Marathon through 13.1 miles. ''I'm definitely strong,'' he says.
Cox is shooting for a top-10 finish in a field that includes two Rosa-coached Kenyans, defending champion Elijah Lagat and '99 winner Joseph Chebet, plus Olympic gold medalist Gezahegne Abera of Ethiopia, a half-step behind Lagat last year.
The U.S. contingent is stronger than in recent years, with '00 Olympian Rod DeHaven, '96 Olympian Mark Coogan and David Morris, whose best is 2:09:32.
''At Chicago in a field that was very strong I was able to pass a lot of guys the second half of the race,'' Cox says. ''I want to run more aggressively than I did in Chicago and not have as much left at the end.''
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