Double-under
Learn double-unders from scratch: start with single unders, size your rope, fix common faults and build to your first double-under in a CrossFit class.
What the double-under is
A double-under is a jump rope skill where the rope passes under your feet twice in a single jump. It trains coordination, timing, calf endurance and conditioning. Beginners start with single unders, one turn of the rope per jump, and build a steady rhythm and a quiet bounce before trying doubles.
Why it is in class
Jump rope is in CrossFit because it packs coordination, footwork and conditioning into a tool that fits in a bag. Single unders build rhythm and a light, springy bounce, and double-unders demand precise timing between wrists and jump, a kind of focus that spills into every other skill you learn. A minute of skipping also raises your heart rate quickly. In daily life, soft landings and quick feet help when you misjudge a curb, dodge something on a trail, play tag with kids, or simply want to feel springy on your feet rather than heavy. Many adults have not jumped rope since childhood, and getting the rhythm back is a fast, visible win.
Points of performance
What a good rep looks like, from setup to finish.
Size the rope
Stand on the middle of the rope with one foot and pull the handles up. For most beginners, the ends of the cable reach somewhere around the lower chest. Too long and the rope drags and slaps. Too short and it catches your feet. Your coach can help you adjust it.
Hands by your hips
Keep your hands just in front of your hips, elbows close to your sides, and turn the rope with your wrists rather than your shoulders. Big arm circles slow the rope and throw off timing. Think small circles, as if you were turning two little cranks.
Small, quiet bounce
Jump only an inch or two off the ground, on the balls of your feet, with slightly soft knees. Land softly and bounce again. Stay tall: the rope needs space under you, not a high jump. A quiet landing tells you your ankles are working like springs.
Single unders first
Before doubles, build steady single unders: one turn per jump, in a rhythm you can hold for a minute or more. This is the foundation. If you cannot keep a smooth single rhythm, doubles will feel random. Practice in short sets and stop before you get sloppy.
Add the second turn
For a double, jump just a little higher and snap your wrists faster so the rope passes twice. Many athletes alternate a few singles and one double, then cut the singles over time. Keep the same body position: only wrist speed and a touch of jump height change.
Common beginner faults, and the fix
Donkey kick
What it looks likeThe heels kick back behind the body to make room for the rope, and the athlete bends forward at the hips.
The fixKeep your feet under you and jump straight up with legs nearly straight. Practice bouncing in place without a rope, landing on the same spot every time.
Arms flying wide
What it looks likeThe hands drift out to shoulder height and the rope turns with whole arm circles.
The fixKeep elbows lightly against your sides and turn from the wrists. Holding a small towel under each arm for a set is a common drill.
Jumping too high
What it looks likeEach jump is a big tuck or a high bound, and the athlete is gassed after a handful of reps.
The fixLower the jump to an inch or two for singles and only slightly higher for doubles. Find speed in the wrists, not height in the jump.
Rope catching the toes
What it looks likeThe rope snags on the feet over and over, often at the same point in the rhythm.
The fixCheck rope length first, then timing. Bounce once without the rope to find your rhythm, then start the rope on the same count.
Where you start, and where it goes
Every movement in class has a version that fits you today.
Start here
Single unders with a rope sized to you, in short sets of 20 to 30 with rest. If the rope is new, bounce in place while swinging the rope at your side first.
Next step when: You can do 50 single unders in a row with a smooth rhythm and soft landings.
Building
Single, single, double drills: a few single unders, then one double attempt, repeated in short sets with a focus on the wrist snap.
Next step when: You can string several singles with a double mixed in, and you land the doubles on purpose rather than by luck.
Full movement
Double-unders as written in a class workout, with single unders as the substitute on days when the rhythm breaks down.
Next step when: You can link 10 or more doubles in a set and keep linking them when tired.
Beyond
Large unbroken sets of doubles under fatigue, faster cable ropes and relaxed breathing while you skip.
Next step when: This rung keeps going: aim to hold unbroken sets late in a workout without your shoulders creeping up.
Learning it in your first classes
In your first coached classes, jump rope practice usually happens during the warm-up or a skill block. Your coach will check your rope length, then watch your hand position, jump height and landings. Most beginners spend a stretch of time on single unders before trying doubles, and that is the correct path. Expect the rope to sting your shins or arms now and then; it passes quickly. Tell your coach about any ankle, calf, Achilles or pelvic floor concerns, since jumping can aggravate them, and check with a doctor or physical therapist when it applies. A coach can swap in a no-jump option on any day.
What your first class at O-SEA CrossFit is like · How On-Ramp teaches the movements
Questions beginners ask
How long does it take to learn double-unders?
Learning double-unders takes some people a few sessions and others several months, and both are normal. Progress depends on rope rhythm, calf endurance and how often you practice. Short, frequent practice beats long, frustrating sessions. A few minutes of single unders and double attempts several times a week, plus coaching on hand position, is usually the fastest route.
What should I do if I cannot jump rope at all?
If you cannot jump rope at all, start without the rope passing under you. Hold both handles in one hand, swing the rope at your side and bounce in rhythm with it. Then bounce in place with no rope. When the timing feels natural, bring the rope back for single unders. In CrossFit, a coach can also substitute a non-jumping option.
What jump rope is best for beginners?
A slightly heavier jump rope, or one with a thicker cable, is usually easier for beginners learning single unders and double-unders because you can feel where it is in its turn. Very thin speed cables are fast and unforgiving. Whatever you choose, size it to your height. Your coach can help you pick a rope and set its length.
Why do double-unders make my calves so sore?
Double-unders keep you on the balls of your feet, bouncing again and again, which works the calves and the tissue around the ankle hard. Soreness in the first weeks is common. Build volume gradually, keep the bounce low and warm up your ankles. If you feel sharp pain in the Achilles or heel, stop, tell your coach and see a doctor or physical therapist.
Related movements
Learn the double-under with a coach beside you
Every class at O-SEA CrossFit is coached and every movement scales. Your first one is free.