This calorie-torching cardio and sculpting workout is one of our hardest ever, but Equinox Tabata instructor Raneir Pollard's amazing energy will inspire you to fight for it. Tabata is a form of HIIT (high intensity interval training) that alternates between 20 seconds of intense bursts of work and 10 seconds of rest in four-minute rounds. You don't need any equipment for the workout, but do grab a towel and a bottle of water — you're going to need both. Then press play and get ready to sweat, tone, and burn! Not ready for a full half hour of Tabata? We got you covered! Try this 10-minute workout.