Single, Single, Double….

When double-unders go well, they are a thing of beauty. The rope is a blur as the athlete bounces up and down, relaxed and composed.
When double-unders fall apart, it’s often painful to watch — and to experience. The rope lashes the legs. The rope gets caught under the feet. You feel yourself becoming frustrated and the situation goes from bad to worse, usually ending with a rope getting thrown across the gym.
The movement seems simple, but so much can go wrong. Double-unders require perfect timing and consistency. The athlete must stay relaxed and fluid, which is often easier said than done.
Believe it or not, there are no magic tips or tricks…Unfortunately, we can’t say that there is a simple trick to master them – it just takes practice. You need to put in the time in order to become better.
However, with a little time spent practising, your double-unders will become a thing of beauty, and you can then move on to the next frontier: triple-unders.
The Jump
Often with our first attempts, the instinct is to whip the rope around as quickly as possible in a desperate attempt to get the rope to pass under the feet twice before hitting the ground.
Strangely for some, this is not the best strategy. A fast moving rope does not guarantee a successful double-under, especially for an athlete who is just learning. The rope doesn’t have to move quickly to turn a single into a double; the athlete has to jump higher.
Imagine doing double-unders on the moon. How easy should it then be to keep rotating the rope? The longer we’re in the air, the more we’re able to slow down the speed of the rope. A slower rope is more relaxing, leaving you fresh for the other movements in the workout.
The ideal posture for double-unders is defined by a tall, upright, and straight body. Making sure the back of the neck is long, the chin is tucked in and the core muscles are tight. The calves should be doing most of the work. Imagine your body is a pogo stick, and your calves are the spring.
The next step is to feel the difference in height between singles and doubles. With singles, the athlete can afford to stay low to the ground. Here, the heels lightly touch the ground and it helps the athlete feel how to turn the rope with his wrists instead of rotating his arms.
When you transition to double-unders, we want to think of doing the opposite. Keep the heels as high off the ground as possible and spring from the toes. We want to spring, not absorb energy in to the floor.
The Hands
After mastering the jump, the next essential step of the double-under is learning the positioning of the hands. Poor hand positioning is one of the biggest causes of missed double-unders. As we tire, the hands drift away from the body, which changes the shape of the rope.
Ideally, the elbows should be by the sides and drawn back, with the palms facing forward. If your hands are too tight against your body, it creates a narrow rope shape. If the hands go too wide, the rope shortens. The ideal is a happy medium.
We want the wrist to do the work, meaning the wrist is disengaged from the arm. When the wrist is the primary mover, the forearms and the grip can be relaxed. You’re going to have a hard time clenching your fingers and having loose, fast-moving wrists. In return, if we lock down our wrists, this will promote us to use a shoulder turn, which isn’t good.
Instead, imagine you’ve just washed your hands and you can’t find a towel to dry them with. The fast, snapping motion you’d use to dry your hands is actually pretty similar to the type of action we want to create when performing double unders. The only difference is we are turning that snapping motion into a rotation.
The Timing
The final piece of the puzzle is timing—when to jump. Just like the Olympic lifts, performing double-unders effectively requires patience.
We see that people want to jump too soon when they first see the rope. Instead, the best time to jump is right after the rope passes below the knee. If you think about it – the rope has further to travel than the body. It has a 360-degree orbit to make, and the athlete only has to move up about 4 inches.
You can start prepping for the double-under by bending the knees and loading up, but the minute the feet leave the ground, the rope should be passing under your body. If the timing is correct, half of the double-under (the first rotation) is done the moment you leave the floor. And then the second rotation happens and is completed before you even hit the very top of the jump.
Thinking about your timing can be a good strategy if you find yourself repeatedly stepping on the rope in the middle of a workout. Stop for a second, take a deep breath and start again, but try to slow everything down. You can speed up once you’re in the swing of things, but take some time to establish a slow, controlled rhythm, keeping your body still, bounding from your toes and rotating the handles with your wrists.
Mastery of the Rope
You will know you’ve mastered the double-under when you can consistently do 50 in 30 seconds and 100 in 60 seconds without breaking a sweat. Know you can confidently get through those, maybe with one break, and know how long they take you. 
Practice keeping a relaxed pace with the double-under. Moving faster certainly, increases the chances of tripping and will create more fatigue in the shoulders, traps and arms. You may be three or four seconds slower, but you will definitely be recovered and ready for what comes next.