I love to run—but I detest running uphill. When I hit an incline, my legs burn, I get acid reflux, and I often need to take a break to catch my breath. Jogging over hills is so terrible for me that I ...

At an endurance research conference in England back in 2015, I saw a surprising talk by a guy named Guillaume Millet. Longer races sometimes produce less muscle fatigue, he said. Running inefficiently ...