MuscleOS
Jackknife Sit-Up demoJackknife Sit-Up demo
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Bodyweight

Jackknife Sit-Up

Muscles worked

  • Abs
  • Obliques

How to do it

  1. Lie on your back with arms overhead and legs straight
  2. Lift your arms and legs at the same time so your hands reach toward your feet
  3. Lower both slowly

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