Awaiting the starting gun last Saturday in Santee, Chicago’s Chris Mosier knew something was wrong. His right knee was hurting. But when 15 men strode into the 7:04 a.m. fog at the U.S. Olympic Trials 50-kilometer race walk, Mosier was among them. After two of the 40 laps — 1.55 miles into the 31-mile race […]