Making weight key to female boxers' Olympic dreams

Even fighters who succeeded in making weight had to bid goodbye to their pre-eminence in another weight class. Andrecia Wasson won the welterweight world title in 2010 and was the world's top-ranked 152-pounder in November 2010. She had to move up to 165 pounds in just over a year to take her Olympic shot, entering the U.S. team trials as an unseeded fighter.

Other American fighters couldn't manage it.

Cashmere Jackson was the 2010 national champion at 141 pounds, winning a bronze medal at the world championships. The Cleveland fighter moved down to 132 pounds last year to fit into the Olympic class, but didn't make it to the trials.

Denise Rico was the world's No. 7 fighter at 178 pounds, but the Olympics have no place for her.

The shrinking weight classes have set up furious competition across the world for the debut Olympic spots. Just one fighter in each class at the U.S. team trials will advance to the world championships in China in May, where they must finish among the top eight to qualify for the Olympics.

Even before the classes merged, Esparza's 106-pound class was already the most popular "for all the small girls in the world," she says.

"Now everybody from two or three weight classes is at 112," she said. "But I feel good about it. I never had strength as a boxer before I gained the weight, and now I have it. I have everything now."