Despite high ratings among our testers, staff, and even my PT, I never laced up an Endorphin Speed that I liked—until now. I chalk up my distaste of the first three Endorphin Speeds to their fit. Past ...

Essentially a measure of your cardiovascular fitness or aerobic capacity, your VO2 max is often considered a must-know metric if you’re a runner – especially if you’re looking to improve your running ...