After a blazing U.S. Half Marathon Championship, Estrada seeks a record-setting time at the Carlsbad 5000.

Those who don’t follow the sport of long-distance running may not recognize the name Diego Estrada. But give him a week. On Sunday, the 25-year-old will toe the line at the Carlsbad 5000 and may just win it.

Estrada, who resides in Flagstaff, Arizona, is coming of a fantastic opening to his racing season. In January, he clocked a blazing 1:00:51 to win the U.S. Half Marathon Championships in Houston. That time, which averages 4:38 per mile for all 13.1 miles, was the seventh-fastest time ever run by an American for the half.

Since that breakthrough performance, Estrada says he’s been focusing specifically on putting his best foot forward in Carlsbad. His coach, the legendary Joe Vigil of the Mammoth Track Club, has been giving Estrada more intense workouts like 1K repeats—as much as 7 x 1000m averaging 2:36 per. He’s even been doing mile repeats and has completed an impressive 4 x 1 mile at 4:16 average per with a 4:11 final mile. “For the last 10 days, I feel like I’ve been rounding into decent 5K shape,” he says. “I’m surprising myself, because last year I could only do the mile repeats at around 4:25 [per mile].”

Estrada credits the base work he did in the longer half-marathon training as a factor for his new fitness at the lower distances. “I can hit splits in tempos now that I couldn’t do before,” he admits. “I can grind out faster times in my tempo runs, because I’m prepared psychologically.” Specifically, Estrada aims to run sub-13:20 in Carlsbad. “I know this is aggressive,” he cautions. And rightfully so, since the current 5K American road record (13:24) belongs to Marc Davis who set it on the Carlsbad course all the way back in 1996.

This Sunday in Carlsbad, Estrada squares off against some stiff competition that includes none other than the legendary ace Bernard Lagat, a 10-time medalist in the Olympics and the World Championships. “I know Lagat could get it [the American record], based on the quality of athlete he is,” says Estrada. “But I don’t see, given my training for it, why I can’t get close to it as well.”

Estrada’s predictions aren’t groundless. He has run close to this time (13:30 last year) and says that he’s in much better shape this year. Estrada attributes his success to two things: the mileage he built up in the lead-up to his half marathon victory in January as well as the quality of tempo runs he’s been doing. His overall mileage has dropped down in this intense phase and he says he’s only been averaging more than 60 miles a week.

Serious racing aside, Estrada admits he’s looking to have a lot of fun this weekend. “I grew up in California. There’s a big community there that I’m familiar with. I mean it’s in Carlsbad, it’s so beautiful there with the beach,” he says. “I think it’s the one of the most beautiful cities in California. To me, it’s just a vacation. I mean, I don’t want to dismiss the field there. It’s world-class. You have Olympic and world medalists who will race there. I think Carlsbad is the Diamond League of road races.”

The Carlsbad 5000, known as the “World’s Fastest 5K” will celebrate its 30th anniversary on Sunday. For the first time in its history, the elite races will start and end at the long-time finish on Carlsbad Village Drive. Instead of completing one loop down Carlsbad Boulevard, these runners will make two loops along the shortened straightaway, before heading back home. This key change to the course should make the already-fast race even faster.

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