The Best Workout in the World™®. Founded in West Hollywood in 1998, it’s the original strength and cardio interval fitness experience that provides a dynamic, high-intensity workout that’s as effective as it is fun. Each class offers 50 minutes of an instructor lead HIIT workout, with either a run+lift or strength-driven format. Each day is a particular muscle-driven focus to maximize your effort and balance your workout with proper recovery between days. Curated playlists, one of a kind instructor energy and a strong community is what makes us like nothing else.