Skipping (also known as jumping rope) is well recognized as a great way to burn calories. For example, a 150 pound person can burn 11 calories per minute by skipping at a moderate pace (the same number of calories if the same person ran a 10 minute mile). For individuals looking to take a more advanced approach to skipping, the double under is an amazing exercise to consider.
To get started, a basic jump is a jump rope technique where the person jumping uses both feet at the same time (feet only slightly apart) to jump over the rope. A double under is a jump rope technique where the person jumps higher than a basic jump and completes two passes of the rope under the feet in a single jump.
Exercise Benefits of the Double Under
Although double unders have been used as an effective training exercise for many sports (i.e., boxing, wrestling), it has recently become popularized in many CrossFit gyms. As an anaerobic exercise, it challenges (and helps to improve):
- Cardiorespiratory fitness (heart and lungs)
- Reaction time
- Muscular endurance
It is an advanced exercise that requires a significant amount of control and coordination to do effectively.
Choosing the Right Rope
To determine the right length rope for your height there are two ways to determine this.
- If you have not yet purchased a jump rope, you can determine the total length of the rope (not including the handles) by taking your height (in feet and inches) and adding three feet (36 inches). For example, a 5 foot 10 inch (70 inches) person would need a rope that is 8 feet 10 inches (106 inches) long. If you are 5 foot 6 inches or shorter, add 2 feet 10 inches (34 inches).
- If you already purchased a rope and need to size it to fit, holding handles (one in each hand) place the rope under the arch of one foot. With feet shoulder width apart, flip down the handles and measure the end of the rope to the base of the chest (approximately nipple height). When you flip the handles back up, the ends should end at about the middle of the armpit.
Perfecting the Double Under
Although the definition of the double under is very simple, the exercise itself is not as easy as it seems. The key to performing double unders, especially consecutive ones, is control of movement and being efficient. Below are five key tips to perfecting the double under:
- Master basic jumps first
- Keep legs straight
- Jump high (and increase “air time”)
- Use your wrists (and keep arms in tight)
- Maintain a tight and upright torso
Master Basic Jumps First
Double unders are an advanced technique that requires mastery of basic jumps. Key mastery points for basic jumps include:
- Rhythm and coordination. These two elements are key to jumping rope quickly and efficiently. Without them double unders are virtually impossible to do successfully.
- Bouncing on both feet at the same time, using the balls of the feet only. This is important for double unders to ensure the highest possible jump height because energy isn’t absorbed when heels hit the ground.
- Jumping in one location and not moving around. This is important for double unders to ensure you can maintain control of the jump and avoid trip ups.
Keep Legs Straight
With double unders, you must keep your legs straight (with a slight bend for control and to avoid unnecessary impact to joints) to effectively complete consecutive jumps. Keeping the legs straight conserves energy and removes any variables in movement that can cause tripping up of the rope.
Jump High (and Increase “Air Time”)
In order to accomplish two passes of the jump rope under your feet, you need to jump slightly higher than a basic jump and increase overall “air time”. It is NOT a maximum jump, but a slightly higher jump that gives you enough time to very quickly get the rope to pass twice under the feet. The key to double unders is the balance between generating power with the legs, speed with the arms, and building overall muscular and cardiovascular endurance for consecutive jumps over time.
Use Your Wrists (and Keep Arms In Tight)
To ensure you can get two quick revolutions of the rope with each jump, it is important to keep the arms close to the body and properly positioned:
- Shoulders back and down (so shoulders don’t tire too quickly)
- Elbows tight to sides
- Hands positioned at midline or center-line axis
Arm position is also important as it ensures the rope maintains enough length to avoid trip ups. For example, when the shoulders start to shrug upwards, the rope gets shorter. The rope also shortens when the hands move backward, and the rope can get caught up in the feet.
Maintain a Tight and Upright Torso
To generate more speed to rotate the rope, the body must remain strong and stable so that the rope doesn’t lose speed. For example, when the torso muscles are engaged and the shoulder muscles contract to hold the arms in place, the rope will rotate faster around the body than if the abdominal muscles are relaxed and the shoulders are hunched over. Also, a tight torso ensures the body remains upright, to avoid bending at the hips and tripping up on the rope.
Workout Progression – Double Under
To work on perfecting double unders, try the following workout progression:
- 10 x basic jumps followed by 1 x double under (alternate for one minute)
- 5 x basic jumps followed by 1 x double under (alternate for one minute)
- 10 sec. x basic jumps followed by 10 sec. x double unders (alternate for one minute)
- 10 sec. x basic jumps followed by 20 sec. x double unders (alternate for one minute)
- 5 sec. x basic jumps followed by 30 sec. x double unders (2 sets)
- 5 sec. x basic jumps followed by 45 sec. x double unders (2 sets)
- Maximum # double jumps in one minute (goal of 50 double jumps)
- Maximum # double jumps in two minutes (goal of 100 double jumps)
- Maximum # double jumps in three minutes (goal of 200 double jumps)