BEST FOR: Midfoot-striking minimalists; cool and wet conditions.
THE TEST: Looking to try out less shoe? With just a hint of heel, the ultralight Mix Master Aeroblock is easier to adjust to than zero-drop, true barefoot shoes. But just because it’s pared down doesn’t mean you can’t rail it in the rough: there’s enough foam and sticky rubber to make it capable of real speed. Testers had no trouble going full-tilt on technical terrain, though the most narrow footed found the fit a bit loose. Plus, the shoe doesn’t mind foul weather. The tightly woven, wind-blocking upper is essentially waterproof.
THE VERDICT: Fast, with four-season chops. 8.5 oz; 4-mm heel-to-toe drop.
NEED TO KNOW: HEEL-TO-TOE DROP: The term, popularized after the book Born to Run came out in 2009, refers to the difference between the height of a shoe's heel and the height of the forefoot. (Got a 14-millimeter heel and a 4-millimeter forefoot? The heel-to-toe drop is 10 millimeters.) Whereas a shoe with a traditional heel height (12 to 14 millimeters) all but forces you to heel-strike, a flatter, more minimalist shoe (0 to 5 millimeters) demands midfoot running—the key to an efficient, low-impact gait. Shoes in the middle allow you (sort of) to strike either way, making them good transition shoes. Just remember that a lower heel means your Achilles has to stretch farther with each foot plant. Ease into lower-heeled shoes to give your body time to adjust.