A Guide to Double Unders for CrossFit Workouts

A necessary skill for Crossfit, a double under passes the jump rope twice under your feet for every jump.

The movement requires speed, agility, and coordination to master but rewards your efforts with increased endurance and leg strength.

You can also complete reps for double unders more quickly than you do for an equal number of single unders.

Contents show

What Are Double Unders?

When I joined my Crossfit box for the ramp-up classes, I thought that doing the single unders with a jump rope was strenuous enough. Being just a beginner, I couldn’t sustain the movement for very long.

And then, surprise, I found out that most of the WODs (Workouts of the Day) required the more difficult double unders unless you were a beginner or scaling down.

Instead of the rope passing under your feet once through one rotation like with traditional single unders, it had to pass twice through two rotations.
And the movement had to continue for a specified number of reps or times.

Here’s a video.

Advantages Of Double Unders

Jumping rope works several muscles in your legs, core, shoulders. They also maximize conditioning and endurance, increase agility, and improve rhythm and endurance. They are a great way to warm your body up on a cold day.

You’ll get all these benefits with single unders. However, you’ll get more of them in a shorter time with double unders because of the increased intensity. You’ll also use more calories with double unders than with singles.

For single unders, a 150-lb person burns 150 calories in 20 minutes or 450 an hour. A 200-lb person uses up 190 calories in 20 minutes or 570 an hour.
For double unders, the 150-lb person uses 300 calories in 20 minutes and 880 an hour. A 200-lb person uses 400 calories in 20 minutes or 1,200 an hour.

Disadvantages

Double unders are difficult, requiring far more coordination and skill than single unders. It’s not likely that you’ll succeed at the movement your first few times doing it. It does require constant practice to slowly build up the skill.

Because you’re doing twice the exertion, double unders also require far more endurance than single unders.

Learning The Movement

Needless to say, my first efforts at double unders proved to be stumble-overs with me resorting to single unders during the WODs.

Luckily, good single unders act as a foundation for double unders.

Keep your body in a straight vertical line with your elbows close to your sides and your hands slightly in front of your hips.
You need to jump efficiently from the balls of both feet while rotating the jump rope from the wrist.
Avoid rotating the shoulders or the elbows, which can slow down your movement. Only wrist rotations are quick enough to progress to double unders.

Once you become proficient in doing single unders, you can tackle the more complex exercise. Focus on jumping higher with a faster turn of the wrist.

Improving

Don’t expect to do several double unders the first time out. Doing just one is an achievement. You can then improve by following this progression.

Don’t forget to do each set as continuously as possible.

No rope. If you can’t use a jump rope at all, try doing a single under without the rope. You then won’t have to worry about the cable getting in your way. Be sure to do all the actions, such as rotating from the wrist and jumping on the balls of your feet.
You need to be proficient at single unders before attempting the rest of this progression.
Single-single-double. Do two single unders in a row followed by one double under.
Singles and doubles. Alternate single unders and double unders equally.
As many doubles as possible. Do as many double unders as you can, followed by a single under.

As you become more skilled, you can eliminate single unders from the rep scheme.

Mistakes To Avoid

Even after you’ve become experienced at double unders, you may miss them occasionally. This is nothing to worry about. Just remember how you used to stumble sometimes with single unders.

However, if you’re having trouble performing consecutive movements, you may be repeating the following mistakes, which are easy to fix.

The rope hits your feet or shins. You’re jumping too early. Wait until you see the rope in front of you before you begin to jump.
The rope is too short to clear your legs or your arms get tired too quickly. You’re rotating from the elbows instead of from the wrists. Go back to single unders and rotate from the wrist. When you’ve mastered that, move on to double unders but continue with the wrist rotation.
Double jumping. You’re confusing the double under with double jumping. Practice jumping higher more slowly, starting with a single under. Then keep the height but do double unders.
You tire too easily. You’re moving your legs, which are the largest muscles in your body, too much. You may be bending at the knees or kicking your feet forward so the rope gets under your feet. Keep your legs straight and jump straight up higher and more slowly.

What Jump Ropes To Use

Because speed makes double unders better, you want a light rope that you can spin more quickly.

However, when you’re starting out with double unders or primarily doing single unders, you want a heavier rope because it is easier to control.

You can learn all about the best jump ropes for CrossFit in this post, but below are some helpful tips on choosing one.

For Beginners

A coated wire cable weighing 3 to 4 ounces with plastic or metal handles works well if you’re a beginner learning single or double unders.

You can then feel the rope move around your body, which helps you time your jumps.

You don’t want anything heavier unless you need the extra effort to increase strength, endurance, and calorie loss.

As for the length of the cable:

If you’re buying a custom jump rope, you can specify that the length of the cable should be your height plus 3 feet.
If you’re using a rope at a Crossfit box, step on the middle of the rope with one foot. Lift both handles up as far as they’ll go. If the ends of the cable reach your armpits or about an inch less, the cable is the correct length.

For Double Unders

If you’re experienced at double unders and want to get better, look for a jump rope with the following specs:

The lighter the rope, the better because you can move the cable faster. Anything under 3 ounces is ideal. Wire cables are lighter than coated versions but can be more painful if they hit you on the shins or feet.
The rope should only go over your head by about 4 to 10 inches when you jump so it can turn over more quickly. Ask a friend to take multiple pictures or a video of you jumping rope. When you view the images, you’ll see how high the cable goes and estimate how much to shorten it by.

Speed Ropes

Speed ropes are ideal for double unders if speed and efficiency are your goals.

They were originally designed for jump rope competitions where athletes try to accumulate as many revolutions as possible within specific time periods, such as 30 seconds, one minute, or three minutes.

Speed rope cables are made from aircraft-grade steel wire that is braided to minimize air resistance. The entire cable weighs about an ounce.
Handles may be made of plastic or aircraft-grade aluminum. More expensive robes have precision bearings in the handles to improve the speed of each revolution.

Speed ropes are most useful in Crossfit WODs or competitions where AMRAP (As Many Reps as Possible) is the goal whether you’re doing single or double unders.

WODS To Try

The number of WODs you can do with double unders are limitless. These are just a few examples.

Interval Doubles

Dave Hunt from Crossrope offers this quick four-minute double-under workout. Do 15 seconds of double unders followed by 15 seconds of rest. Repeat for eight sets. Then write down the number of reps for each round. You can either pick your lowest reps for one round or the total reps. In either case, shoot for more reps the next time you do the workout.

Annie

Annie is one of the benchmark Crossfit workouts that you score so that each time you do it, you can gauge your fitness progression.

50-40-30-20-10 reps for time

Double unders.
Sit-ups. Lay face-up on the floor with your knees bent and your feet flat on the floor. Reaching forward and up with your hands, bring yourself into a sitting position. Then lower your back down to a lying position.

Do the movements as listed: 50 double unders followed by 50 situps. Then 40 double unders and 40 situps. Continue until you reach 10 double unders followed by 10 situps.

The descending reps means you go faster toward the end, but you can break it up in the early rounds.

Shoot for the following times:

Beginner: 10-12 minutes
Intermediate: 8-10 minutes
Advanced: 7-8 minutes
Elite: Under 6 minutes

Megan

Another benchmark workout drops the reps but adds an equipment movement.

21-15-9 reps for time

Burpees. From a standing position with feet shoulder width-apart, drop into into a pushup position with hands shoulder-width apart. Do one pushup and then move your feet forward. Jump into a standing position and clap your hands above your head. Then drop down to the starting position.
Kettlebell swings with a 53-lb kettlebell for men and 35 lbs. for women. With your feet slightly more than shoulder-width apart, hold a kettlebell between your legs with both hands. Hinging at the hips, push your hands with the hips and straighten your legs to raise the kettlebell above your head and then bring it down to the starting position.
Double unders.

Do the movements as listed: 21 burpees followed by 21 kettlebell swing followed by 21 double unders. Then do 15 burpees followed by 15 kettlebell swings followed by 15 double unders. Finish with 9 burpees followed by 9 kettlebell swings followed by 9 double unders.

Brian McAleese

This hero workout remembers Brian McAleese, a new New York firefighter. It was developed by 555 Fitness as part of the 343 Honor WODs, one for each of the 343 New York Fire Department member who died on September 11, 2001 during the attack on the World Trade Center.

For time, 75 thrusters with a 95-lb barbell for men and 65 lbs. for women. Start with a barbell across the front of your shoulders and feet shoulder-width apart. Drop into a full squat. Stand up and push the barbell up into a shoulder press.
20 double unders at every minute

Do 75 thrusters as quickly as possible. However, at every minute of the workout, do 20 double unders. The more quickly you finish the thruster, the fewer double unders you have to do.

Instead Of A Rest

Instead of doing the timed rest specified in a WOD, do double unders instead. This can be extremely challenging because it replaces your recovery period with high-intensity exercise.

For example, your workout may have you repeating a cycle of a five-minute AMRAP of pullups followed by a minute of rest. Instead of taking the rest between pullups, do as many double unders as you can. Your score can total the number of pullups and the number of double unders.

Alternatives To Double Unders

You may not be able to do double unders for many reasons. Here are some alternatives.

Single Unders

When you’re just starting, single unders are a convenient alternative to doubles at a 3:1 or 2:1.

For example, if the WOD calls for 50 double unders, do either 150 or 100 single unders instead.

If you can only do a few double unders, set a limit for your attempts that equals the time a proficient athlete could complete all the reps of double unders. For example, if someone can complete 60 seconds to do 30 double unders, give yourself a minute to work on your double unders.

If you can do a single, single, and double under continuously, halve the number of reps. For example, instead of doing the prescribed 50 double unders, do 25.

You can probably complete the lower number in the time it takes a proficient athlete to complete the higher total.

Bodyweight Alternatives

Mimicking the double-under movement without a jump rope is one way a beginner can learn the exercise.

Other exercises for beginners include running in place with high knees or butt kickers: as you run in place or forward, bring your heels to your glutes.

A more strenuous alternative that uses only your bodywright consists of tuck jumps.

Stand up straight with your feet shoulder-width apart.
Drop your glutes into a squat position and move your arms behind you.
Drive your arms up while pushing off the floor with your legs.
Lift your knees toward your chest as you fly to the top.
Keep your knees bent to absorb the impact as you land on both feet.

Learn about more jump rope alternatives in this post.

With Equipment

If you have an injury that prevents you from jumping, your box will probably have the equipment that you can use for the following double-under substitutes:

Assault Bike. You’ll work out all the muscles of the leg and engage your upper body on an assault bike with less stress on the joints and no impact. The harder and faster you go, the more resistance you’ll feel and the more intense the workout. Avoid twisting or moving from side to side and prevent your elbows and knees from bowing out to the sides.
Give equal effort to pushing and pulling with your arms as you do with pedaling. Focus on going forward for the first half of the workout and then going backward for the next half to work your muscles differently.
Russian Step-ups. This exercise also works out your lower and upper body without the impact of jumping.
With a dumbbell or kettlebell in each hand, step on a box with the right foot and kick your left knee up to your chest as you raise yourself on the box. Drop your left leg down as you lower your body down to the ground. Do several reps on one leg before switching to the other leg.
Kettlebell Swings. This full-body exercise builds muscle depending on how much weight you swing. You can use it if you have an injury that minimizes foot movement because you plant your feet on the ground.
Rope Whips. This substitute avoids moving the knees or the feet but provides the same explosive moment and accelerated heart rate of double unders by focusing on the upper body.
Grab a battle rope in each hand and stand with your feet in a wide squat. Sit into a partial squat and then quickly move your hands up and down to form waves on the ropes. You can increase the intensity by using bigger movements when you wave the ropes.