BEIJING - Duluth's Kara Goucher had resurrected her career while training with legendary distance runner Alberto Salazar, going from "sitting on the couch eating peanuts" four years ago to attaching herself to the lead pack on Friday in the Olympic 10,000 meters.

She took bronze at last year's world championships on a blistering day in Japan, and now she was running her kind of race, tailing the leaders, hoping her self-described strength and toughness would help her pick off the leaders as the Beijing humidity took its toll.

Then, at about 6,000 meters, she did what no distance runner can do when lungs and thighs begin to burn.

She gave herself an excuse.

"It was weak," she said.

It was costly.

Goucher ran a personal best of 30 minutes, 55.16 seconds and finished 10th in the Olympics. A few years ago, when she was full of self-doubt and those dreaded peanuts, she would have been thrilled. Friday, she almost cried.

"Well, you know, I'm crazy," she said. "I thought I could win. The pace was quick and it was starting to get hot, and I made a major mistake. I started thinking about Tuesday, and I let that become a reason that it's OK not to gut it out.

"It was a big mistake, and I'll be thinking about it for a long time."

Goucher will run in the 5,000 meters on Tuesday. When the leaders sprinted ahead on Friday, she told herself saving energy would be wise. "My sports psychologist is going to kill me," she said. "Because that cost me a much better performance."

Ethiopia's Tirunesh Dibaba blazed through the final lap to win in 29:54.66, just ahead of Turkey's Elvan Abeylegesse. Goucher's teammate, Shalane Flanagan, took the bronze, a year after Goucher gave the U.S. women their first medal in the 10,000 at a world championship in 15 years.

Flanagan credited Goucher with helping raise the standards for U.S. women's distance runners, and admitted that she wasn't sure she had taken a medal until someone on the track confirmed her place after the race.

About the time Goucher backed off, Flanagan poured it on. "There was a point in the middle of the race where I thought, 'This could go really well or really bad,' " Flanagan said. "Because it started to hurt. So I found my happy place and thought of my favorite run at home and said, 'What am I holding back for? I've trained my butt off forever, and I'm just going to let it go.' "

Now Goucher wishes she had thought of that. "Honestly, I'm really sad," she said. "I think I'm better than that."

Her voice started cracking, and she said, "I guess if a really bad day is 10th, that's fine, but I don't race to be 10th in the Olympics."

Goucher ran in place for a moment, to demonstrate her energy level, and said: "I have so much stuff left right now, which is the worst feeling, because I'm not laying on the track. Regret is the worst feeling. I'm not saying I would have done any better, but I definitely did not risk it, and that was my only goal for the race, was to risk it."

Does mental toughness matter in distance running? Flanagan spent the early part of the week vomiting and experiencing what she politely called "G-I" problems. That stands for gastrointestinal, and because she feared a positive drug test, she treated herself with nothing stronger than Immodium and water.

She cut back on training "to save those body fluids," and trailed Goucher until she decided to risk a burst, and found her happy place.

Goucher is hoping she'll find hers on Tuesday.

"Oh, you'll see a different animal on Tuesday," she said. "I feel like I let a lot of people down."

She said it again, as if to convince herself: "I'll be a different animal on Tuesday."

Jim Souhan can be heard Sundays from 10 a.m.-noon on AM-1500 KSTP. • jsouhan@startribune.com

PhelpS' quest for 8 golds The following is a breakdown of U.S. swimmer Michael Phelps' two Olympic victories and his remaining races. Sat., Aug. 9 • 1-for-1 400 individual medley Sunday • 2-for-2 4x100 freestyle relay Monday • 3-for-3 200 freestyle Tuesday • 5-for-5 200 butterfly 4x200 freestyle relay Thursday 200 individual medley (9:48 p.m.) Friday 100 butterfly (9:10 p.m.) Saturday 4x100 medley relay (9:58 p.m.) Central Daylight Time