COLORADO SPRINGS, Colo. — Marlen Esparza added another championship to her run of dominance.

COLORADO SPRINGS, Colo. — Marlen Esparza added another championship to her run of dominance.

Esparza won her sixth straight title at the USA Boxing national championships Saturday night, outpunching Tyrieshia Douglas for the women's flyweight crown.

Esparza, Douglas and the two other fighters who reached the 112-pound quarterfinals during the weeklong championships at City Auditorium qualified for the U.S. Olympic Team trials to be held early next year at a site to be determined. At stake will be the chance to compete for the U.S. at the 2012 London Games, where women's boxing will make its Olympic debut.

The 22-year-old Esparza outpointed Douglas 27-16.

She said she used her stamina and conditioning to her advantage, noting that Douglas had started well and but didn't seem to finish strong in winning her bouts earlier this week.

"I had seen her get tired in her fights and I knew what kind of shape I was in," Esparza said. "When she had energy, we were going at it, but as soon as she got down it was super easy. That's really how it played out."

Douglas took a single-minded lesson out of her latest loss to Esparza.

"Just keep fighting," she said.

In other finals, David Carlton of Cincinnati scored a 27-20 decision over Louie Byrd of Denver in the men's 108-pound weight class; John Franklin of Fort Carson, Colo., scored a 13-10 decision over Oscar Cantu, Kingsville, Texas, at 114 pounds: Joseph Diaz Jr. of El Monte Calif., registered a 14-11 decision over Joet Gonzalez, Glendora, Calif., in the 123-pound class.

Also, Jose Ramirez of Avenal, Calif., beat Toka Kahn Clary of Providence, R.I., 28-20 in the 132-pound class; Semajay Thomas of Chicago had a 23-12 decision over Thomas Duquette of Waltham, Mass., in the 141-pound division; Errol Spence of DeSoto, Texas, emerged with a 13-7 decision over Luis Olivares in the 152-pound class and Jordan Shimmell of Hudsonville, Mich., won his second title in three years with a 14-8 decision over Andrew Tabiti of Las Vegas.

Jesse Hart of Philadelphia won the 178-pound weight division over Jerry Odom of Bowie, Md., on a medical disqualificaion. Odom sustained a gash on his lip that required a dozen stitches to close earlier this week. There also was a medical disqualification in the super heavyweight bout (201-plus pounds) with Jonathan Hamm of St. Paul, Minn., declared the winer over Laron Mitchell of San Francisco.

Queen Underwood of Seattle defeated Tiara Brown of Lehigh, Fla., 23-21 in the women's 132-pound division and Franchon Crews of Baltimore earned a 15-13 decision over Alyssa DeFazio of Peoria, Ariz., in the 165-pound division.

The top four finishers from each class, men and women, advance to the U.S. team trials. The men's trials are set for July 31-Aug. 6 in Mobile, Ala.