CoreReps OnlyRated 4 out of 10

Jack-knife Sit-up

Log every set of the Jack-knife Sit-up and watch your strength climb. W8M8 is free to download, and Pro is free for your first 3 days.

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Animated demonstration of the Jack-knife Sit-up

How to do the Jack-knife Sit-up

  1. 1Lie flat on your back with your arms extended overhead and legs straight.
  2. 2Simultaneously raise your legs and torso to meet in the middle, forming a V shape.
  3. 3Reach your hands towards your feet as you contract your core.
  4. 4Lower your legs and torso back to the starting position in a controlled manner.

Muscle group

Core

Type

Reps Only

Equipment

None needed

TRACK THE JACK-KNIFE SIT-UP IN W8M8

Add it to a routine, log your sets and reps, and let the W8M8 AI build your programming and set your progression targets. Tracking is free forever. Pro is free for 3 days, then cancel any time.

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