Jackknife Sit-Up

BodyweightIntermediateIsolation
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Quick answer

Jackknife Sit-Up is an intermediate isolation bodyweight exercise that mainly works the abs, with the quads assisting.

Written by the GymStreak coaching team

Muscles worked

Front
Back

Primary

Secondary

How to do Jackknife Sit-Up

  1. 1

    Begin by laying flat on your back with your hands stretched out above your head and your legs together and slightly off the ground. This is your starting position.

  2. 2

    Exhale and as you do, raise your arms and legs up into the jackknife position by pushing your fingers towards your toes.

  3. 3

    Pause the contraction for a moment at this point, then slowly return to the starting position, keeping tension in your abs throughout.

Form cues

  • Try to keep you legs as straight as possible when raising them for maximum difficulty. You can bend your knees slightly to make it easier.

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