ALBUQUERQUE — The morning sky was as clean and blue as a gas flame. Thin clouds hung like a fleecy collar over the Sandia Mountains, as if to warm against the lingering chill, as Dathan Ritzenhein set out for his run on feet that were famously fast and brittle.


He will be among the favorites at the New York City Marathon on Nov. 7, and is expected to battle Meb Keflezighi, the defending champion and 2004 Olympic silver medalist from San Diego, and Haile Gebrselassie, the world-record holder from Ethiopia. But Ritzenhein’s career has been as undulating in the last two years as the New York course, full of rises and depressions and unexpected turns caused by feet that have alternately elevated and betrayed him.