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  1. Home
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  3. Exercises
  4. /
  5. Core & Abs
  6. /
  7. Tuck Crunch

Exercise guide

Tuck Crunch

  • Beginner
  • Compound
  • Rep-based
  • Waist

The Tuck Crunch is a dynamic core exercise that targets the entire abdominal wall by simultaneously bringing the upper and lower body together. It effectively builds functional core strength and improves stability by engaging the rectus abdominis and hip flexors.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Tuck Crunch demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs

Secondary

  • Erector spinae

Equipment

  • Body weight

Setup

  1. Lie flat on your back on a mat with your legs extended and arms by your sides.
  2. Engage your core to press your lower back firmly into the floor, eliminating any arch.
  3. Lift your heels 2-3 inches off the ground and place your hands lightly behind your ears or reaching toward your feet.

How to do it

  1. Exhale as you simultaneously crunch your upper body upward and pull your knees toward your chest.
  2. Contract your abs hard at the top of the movement, bringing your knees and chest as close together as possible.
  3. Inhale and slowly lower your torso and extend your legs back to the starting position.
  4. Maintain a controlled 2-1-2 tempo, ensuring your heels and shoulder blades do not fully rest on the floor between reps.

Form checklist

  • Keep your lower back in contact with the floor throughout the entire movement.
  • Avoid pulling on your head or neck; use your abs to lift your shoulders.
  • Keep your chin tucked slightly toward your chest to maintain a neutral cervical spine.
  • Ensure the movement of the upper and lower body is synchronized.

Pro tips

  • Focus on the 'hollow body' sensation during the extension phase to keep the deep core muscles engaged.
  • Pause for one second at the peak of the tuck to maximize the mind-muscle connection and peak contraction.

Make it harder

  • Perform the movement with a medicine ball held between your knees to increase the load on the lower abs.
  • Slow the eccentric phase to 4 seconds to significantly increase time under tension.

Frequently asked

What muscles does the tuck crunch work?
The tuck crunch primarily targets the abs, and also works the erector spinae as secondary muscles.
What equipment do you need for the tuck crunch?
The tuck crunch requires no equipment — just your body weight.
Is the tuck crunch good for beginners?
Yes. The tuck crunch is a beginner-friendly movement and a strong foundation to build on.

Related exercises

  • 3/4 Sit-UpBeginner · abs and obliques
  • 45 Degree Bicycle Twisting CrunchIntermediate · abs and obliques
  • 45 Degree Lean Back Alternate Knee RaiseBeginner · abs and obliques
  • 45 Degrees Arms PlankIntermediate · abs, deltoids, obliques, and pectorals

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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