Double unders are a jump rope exercise where the rope passes under the feet twice for each jump. This requires a combination of speed, timing, and coordination. Athletes often use double unders to improve cardiovascular fitness and agility. To perform double unders, jump higher than a standard jump and swing the rope faster. Proper technique involves keeping the elbows close to the body and using the wrists to control the rope's movement. Many fitness enthusiasts incorporate double unders into their workouts for added intensity and to enhance their overall jump rope skills.