Jack knife (Pilates)

From the roll-over position, you send the legs up toward the ceiling so you balance high on the shoulders, then roll the spine down with the legs angled over your face.

Roll-over (Pilates) family

Jack knife (Pilates)

Standard option

From the roll-over position, you send the legs up toward the ceiling so you balance high on the shoulders, then roll the spine down with the legs angled over your face.

DemandHard

Equipment requiredFloor space

Muscle focusAbs · Back · Triceps · Hamstrings

Written instructions available. A verified 3D demonstration has not been built for this variation.

Source-researched guide. Clinical review is pending.

How to move

Lie with your arms by your sides, legs to the ceiling.
Breathe out and roll the legs over until they are parallel to the floor, as in the roll-over.
Breathe in, press the arms down and send the legs up toward the ceiling, hips high, weight on the shoulder blades.
Breathe out and roll down one segment at a time, keeping the ankles in line with your eyes as you lower.
Repeat with control.

Form cues

Press the arms into the mat to lift.
Keep the ankles in line with your eyes as you lower.
Avoid: any weight on the neck, or collapsing on the way down.

Practice and cautions

3 reps (the classical sequence uses 3). A suggested starting point. No trial has tested this move on its own.

Avoid it with neck or spine injuries, and learn the roll-over first. Avoid it with osteoporosis and in pregnancy. This is movement education, not an assessment or treatment prescription. Stop for sharp or increasing pain, dizziness, numbness or tingling; seek individual guidance for symptoms, injury or restrictions.

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Sources and review status

Sources support the educational description; they do not establish that this exercise is suitable for you.

No variation is labeled clinically validated.

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What it works

Muscles

Main: Abs. Also: Back, Triceps, Hamstrings.

Equipment

None: body weight and floor space.

Level

Advanced. See the easier and harder options above.

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Questions people ask

What muscles does the Jack knife (Pilates) work?

Mainly the abs, with help from the back, triceps and hamstrings.

What equipment do I need for the Jack knife (Pilates)?

No equipment: your body weight and a little floor space.

Is the Jack knife (Pilates) good for beginners?

It is an advanced move. Build up to it with the Roll-over (Pilates roll-over with legs spread) first.

What is an easier alternative to the Jack knife (Pilates)?

Try the Roll-over (Pilates roll-over with legs spread). Both are written steps in the same progression.

How do I make the Jack knife (Pilates) harder?

Progress to the Control balance (Pilates), or add load, range or slower lowering once your form is solid.