OMAHA — Missy Franklin said she relished the challenge, racing in the finals of the 100-meter backstroke at the Olympic Trials on Tuesday night mere minutes after grinding through the semifinals of the 200-meter freestyle, but the experience dissolved into disappointment. The 2012 Olympic champion in the 100 backstroke will not race that event in Rio after finishing seventh, 1.22 seconds behind the winner from the University of Georgia, Olivia Smoliga.