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All exercises

Jackknife sit-up

Intermediate

Jackknife sit-up is a isolation bodyweight exercise for the abs, also working the quads.

What it works

Primary muscle

Abs

Also works

Quads

Equipment
Bodyweight
Movement
Core
Type
Isolation
Logged as
Reps
Suggested rest
1 min

How to do it

  1. 1Lie flat on your back with your legs extended and your arms overhead.
  2. 2Engage your core and lift your legs and upper body simultaneously, reaching your hands towards your toes.
  3. 3Pause for a moment at the top, then slowly lower your legs and upper body back down to the starting position.
  4. 4Repeat for the desired number of repetitions.

What to do instead

  • Band jack knife sit-upResistance band
  • Sit-upBodyweight
  • Half sit-upBodyweight
  • Quarter sit-upBodyweight
  • Prisoner half sit-upBodyweight
  • Assisted sit-upMachine

Easier variations

  • Assisted sit-upMachine
  • 3/4 sit-upBodyweight
  • Half sit-upBodyweight
  • Prisoner half sit-upBodyweight

Harder variations

  • Janda sit-upBodyweight
  • Weighted decline sit-upWeight plate
  • Decline sit-upBodyweight
  • Band jack knife sit-upResistance band
Logged today · 1 min restJackknife sit-up

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