Gear-obsessed editors choose every product we review. We may earn money if you buy from a link. How we test gear. Cross-training is a valuable and often neglected component of endurance training. Recent studies show that regular cross-training—a plyo circuit, a bootcamp-style workout class, or even some boulder hopping—yields real results on race day. If you’re considering adding some variety to your routine, or if your schedule already includes cross-training, you should be wearing shoes that can withstand the stress and protect you from injury. For most, that means swapping your running shoes for trainers with more support. Consider a 2017 study published in the European Journal of Applied Physiology that showed introducing well-trained ultramarathon runners to explosive plyometric workouts for just 12 weeks was enough to see a 4 percent increase in running economy. In other words, the runners showed a 4 percent decrease in the amount of energy and oxygen required to maintain race pace. Cross-training works because running the same miles for months is monotonous for our legs. Our muscles adapt to the work, become more adept at managing stress, and, because they’re never pushe...