High-intensity interval training isn’t a new concept, but the Shred415 workout and East Side studio (2165 N. Prospect Ave.) keeps it interesting while you sweat your butt off. Each workout is broken into four 15-minute intervals (hence the name) alternating between treadmill drills and strength-based endurance exercises on the floor. The lights are low, and the music is so loud, you won’t hear your heart pounding. You never have to do the same exercise more than once, and trainers tailor classes for every fitness level.
