It’s not that Darya Domracheva hasn’t been fast before. No, that’s not what makes her form in the last several weeks so impressive. She’s always been fast: the 25-year-old Belorussian biathlete has won eight races and picked up 27 more podiums, including Olympic bronze, in the past few seasons. But in many of those victories, Domracheva has won by sheer force of will, digging in to the intense head-to-head competition offered up by the World...