If you have four minutes...jump and squat. Rest. Repeat.
The Tabata Protocol, which sounds like the title of a Robert Ludlum novel, is actually a mini-workout that really makes a difference. Originally named after the Japanese fitness researcher Izumi Tabata, this interval workout alternates 20 seconds of ultra-intense exercises with 10 seconds of rest, for a grand total of four minutes. While working with Olympic speed skaters in the mid-1990s, Tabata found that this type of workout helped build muscle and improve aerobic and anaerobic capacity. More recently, Michele Olson, PhD, a professor of exercise science and a principal researcher at the Auburn University at Montgomery Kinesiology Laboratory, revealed that a Tabata-style workout of squat jumps burned 13.5 calories a minute and doubled calorie-burning potential for 30 minutes afterward. Olson's research also showed that this four-minute routine was as effective as five times the amount of traditional cardio. Try it yourself: Do 20 seconds of a full-body move like squat jumps at maximum effort (it should hurt), then rest for 10 seconds. Repeat this circuit continuously for four minutes.