Create a Solo "Class"
Channel the adrenaline of a group running class with a well-thought-out playlist, says Harley Rodriguez, a trainer at Barry's Bootcamp, which alternates treadmill segments with strength sets. Use music to time your intervals, choosing songs with up-tempo choruses that get you pumped to pick up your pace with each refrain. "In your head, say: I'm doing a 30-second sprint in four, three, two, one—then give it your all," Rodriguez says. If you're spurred by the competitive spirit of a group class, hop on a treadmill next to someone who looks like a strong runner. You can race them by setting your pace to something higher than theirs—they'll never need to know! (Try this running interval playlist for starters.)