Cocoons

beginner strength exercise · body weight · targets abs

Body part: waist
Primary target: abs
Equipment: body weight
Difficulty: beginner

Cocoons are a dynamic ab exercise performed lying flat, then drawing both knees toward the chest while simultaneously curling the upper body forward, creating a 'cocoon' position with the body folded inward. The motion combines lower-ab work (the knee draw) with upper-ab work (the curl) in a single rep, producing efficient combined ab training. This is one of the more demanding bodyweight ab exercises due to the simultaneous upper and lower body motion. The full-body folding produces meaningful stimulus across the entire abdominal region — the rectus abdominis (front abs), the transverse abdominis (deep core), and the hip flexors all engage to drive the motion. Where this earns its place is as advanced ab work in core training programs. The combined motion produces more stimulus per rep than isolated exercises, making it efficient for time-limited training. Combined with planks and rotational work, cocoons complete comprehensive ab programming.

Why train the Cocoons?

Combines upper and lower ab work in one efficient exercise.
Engages the entire abdominal wall through the simultaneous motion.
Builds hip flexor strength alongside ab work.
Time-efficient for core training.
Pairs naturally with planks for compound core training.
Costs nothing and requires no equipment.

How to do the Cocoons: step by step

1Lie flat on your back with your knees bent and feet flat on the ground.
2Place your hands behind your head with your elbows pointing outwards.
3Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle.
4Pause for a moment at the top, then slowly lower your upper body back down to the starting position.
5Repeat for the desired number of repetitions.

Muscles worked

Primary

abs

Secondary

hip flexors, lower back

Common mistakes to avoid

Bouncing through reps
Slow controlled motion produces ab engagement.
Pulling on the neck
Hands-free or hands lightly behind head. Don't pull the neck forward.
Cutting range
Bring knees and chest together fully. Partial reps reduce stimulus.
Letting feet touch the floor between reps
Keep feet hovering slightly above floor to maintain ab tension.
Holding the breath
Exhale on the curl, inhale on the extension.

Easier and harder variations

Easier

Bend knees more during extension. Or perform separate components — reverse crunch then upper crunch — instead of combining.

Harder

Slow tempo (3 seconds in each direction). Or hold contracted position 1-2 seconds. Or add ankle weights.

Alternative exercises

V-up
Similar combined motion with straight legs. More demanding.
Reverse crunch
Lower-ab focus only. Easier alternative.
Hollow body hold
Isometric version. Foundation for more advanced ab work.

How to program the Cocoons into your training

Sets and reps: 3 sets of 12-20 reps. Frequency: 3 times per week. In core sessions: 3 sets of 15 cocoons, 3 sets of 30-second planks, 3 sets of 15 Russian twists.