On Friday, American biathlete Tim Burke finished fourth in the 10 k World Cup sprint in Oberhof, Germany, 20.1 seconds behind France’s Martin Fourcade. A few years ago, it wouldn’t have been at all unusual to see Burke in that position, or even on the podium. He’s the 2013 World Championships silver medalist in the 20 k individual, but he had a couple of tough seasons, with compartment syndrome surgery in the middle. Last year,...