It started with a workout on your phone. Now it’s 5:30 a.m. and 12 strangers are shouting your name as you finish a circuit. Ropes, lunges, mountain climbers. It’s all pain, but it’s the good kind. The kind that makes you come back for more. Nike Air Zoom SuperRep 3. HIIT off on the right foot. (Left is fine, too.) Never done moving. Tap to shop.