Jackknife Sit-Up

AbsBodyweightBeginnerCompound
Jackknife Sit-Up — start position
Start
Jackknife Sit-Up — finish position
Finish
Muscles worked
PrimaryAbs

How to do it

  1. 01

    Lie flat on the floor (or exercise mat) on your back with your arms extended straight back behind your head and your legs extended also. This will be your starting position.

  2. 02

    As you exhale, bend at the waist while simultaneously raising your legs and arms to meet in a jackknife position. Tip: The legs should be extended and lifted at approximately a 35-45 degree angle from the floor and the arms should be extended and parallel to your legs. The upper torso should be off the floor.

  3. 03

    While inhaling, lower your arms and legs back to the starting position.

  4. 04

    Repeat for the recommended amount of repetitions.

In the app

Jackknife Sit-Up needs no kit, so it appears whenever the day's window has room for it. Its minutes come from Rule 2 (Sessions are built to fit, never guaranteed, graded product): the window sets how long it runs, never the other way round.

If a machine is taken the engine swaps a same-pattern movement and says why.

Same pattern, with kit

Same movement pattern, same primary muscles — swap by what you have.

With other
With bodyweight
With machine
With cable

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