In any long-distance run, from the half marathon to ultras, the winner isn’t the runner who looks the best right off the starting line, but the one who stays the strongest as the miles stack up.Fatigue resistance—the ability to avoid the effects of running that force you to slow down—is an important objective for all endurance athletes to stay strong, regardless of the sport. But while VO2 max and lactate threshold training might get the spotlight for staving off fatigue in milers and half marathoners, respectively, those going longer need to focus on another training strategy.“We start having other variables that begin to compete [with VO2 max and lactate threshold] for priority,” Cliff Pittman, coaching development director at Carmichael Training Systems and Molly Seidel’s ultramarathon coach, tells Runner’s World.…