Erin Gregoire crossed the finish line of the Houston Marathon, looked at her watch, and smiled. In her debut at the distance, she ran 2:42:55—well under the qualifying time of 2:45:00 she needed for the Olympic Marathon Trials. In what has become a complex case, however, Gregoire was denied entry into the Trials, because the differential between her gun time (2:54:54) and chip time (her 2:42:55) was too large. And the day of the Houston Marathon (January 19) was the final day of qualifying, so it was her last shot at getting into the race. “Obviously it was an incredible...