Seven minutes for a workout — who doesn't have time for that? That's why we've been loving this quick circuit workout from the American College of Sports Medicine, which burns major calories in a short amount of time. Keeping the intensity up — and the rest periods short — is key, so make sure you are pushing yourself during each 30-second spurt! You'll need a mat and a chair or bench. Repeat the circuit up to three times. Learn how to do all the moves here, and get the printable poster of this seven-minute HIIT workout here.