Atkinson just missed a spot on the medal stand with a fourth place finish in a time of 1:06.93, while Larson was right behind in sixth place with a time of 1:06.96. Lithuania's Ruta Meilutyte took the gold in 1:05.47, followed by Rebecca Soni (USA) in 1:05.55 and Satomi Suzuki (Japan) in a time of 1:06.46.
For Atkinson, a 2010 senior at Texas A&M, it was the highest individual finish ever by a Jamaican swimmer at the Olympic Games. Larson, who just finished her sophomore season with the Aggies, posted the highest finish ever by a current A&M swimmer at the Olympics, edging out Julia Wilkinson's seventh place finish in the 200 IM in 2008.
It was an eventful final for Larson, who was the only one of the eight 100 breaststroke finalists to dive in when the starting horn malfunctioned in front of a near-capacity audience at the Aquatic Centre and millions watching on television.
"I came up and didn't say anything, kind of pretended it didn't happen and that nobody saw that," a composed and upbeat Larson said afterward. She was not disqualified because the beeper went off before swimmers were ordered to take their mark, which Larson already had done.
"It's just a swimmer's reaction to dive in and go," she said. "I kind of noticed nobody else went. I'm glad I didn't keep swimming."
After a short delay to regroup and check on the malfunction, swimmers were told to shed their warm-ups for a restart. The crowd, which included her parents and one of her sisters, cheered for Larson after the mishap. Her thought process was to charge ahead, which took her out too fast in 30.85 at 50 meters.
"I think I dealt with it pretty well," said Larson, who can better put the moment in perspective because she had to sweat out results of a biopsy last summer to determine if she had thyroid cancer. "You have to make some mistakes before you get them all right. It's kind of a bummer that it happened here at this time, but it's not the end. I'll keep going."
She has two years of her college career left at Texas A&M.
"You appreciate the good things when bad things happen," Larson said. "You don't appreciate your toes until you step on them. The next time I race this, it will give me the confidence saying you made this mistake at the Olympics. If you can get over that, you can get over anything."
Aggies in the London Olympic Games (Monday, July 30, 2012)
Alia Atkinson (Jamaica), 1:06.93 (4th)
Breeja Larson (USA), 1:06.96 (6th)
Erica Dittmer (Mexico), 2:16.54 (27th prelims)
Kim Pavlin (Croatia), 2:17.17 (30th prelims)