Plylometrics Shape.com Plyometrics, or jump training, is designed to increase muscular power and explosiveness. According to WebMD, plyometrics “conditions the body with dynamic resistance exercises that rapidly stretch a muscle (eccentric phase) and then rapidly shorten it (concentric phase).” It was originally designed for Olympic athletes and has been around since the 1970s. Now, you’ll find people of all ages getting in on the jumping. If you’re interested in high intensity interval training workouts, Shape.com has a three times a week, lower-body plyometrics workout which can boost calorie burn and improve power, stamina, agility, and speed. And as a bonus, no equipment is needed!