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  3. Exercises
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  5. Core & Abs
  6. /
  7. Frog Crunch Hold

Exercise guide

Frog Crunch Hold

  • Intermediate
  • Isolation
  • Timed hold
  • Waist

The Frog Crunch Hold is an isometric core exercise that targets the rectus abdominis and obliques while minimizing hip flexor involvement by placing the legs in a diamond position. This variation creates intense tension throughout the midsection, particularly focusing on the upper and middle abdominal fibers.

Reviewed by the Crucible Fit team · Updated June 2026

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

Muscles worked

Primary

  • Abs
  • Obliques

Secondary

  • Erector spinae

Equipment

  • Body weight

Setup

  1. Lie flat on your back on a mat with your spine in a neutral position.
  2. Bring the soles of your feet together and let your knees fall open to the sides, creating a diamond shape with your legs.
  3. Place your fingertips lightly behind your ears or reach your arms straight forward between your knees.
  4. Pull your belly button toward your spine to flatten your lower back against the floor.

How to do it

  1. Exhale forcefully and lift your head, neck, and shoulder blades off the mat by contracting your abs.
  2. Hold this elevated position, maintaining a 'hollow' shape with your upper body while keeping your lower back pressed into the floor.
  3. Maintain a steady, shallow breathing pattern while holding the peak contraction for the duration of the set.
  4. Slowly lower your shoulder blades back to the mat with control once the hold is complete.

Form checklist

  • Keep your lower back glued to the floor; do not let it arch.
  • Ensure your shoulder blades remain completely off the mat throughout the hold.
  • Keep your chin tucked slightly toward your chest to avoid neck strain.
  • Maintain the outward flare of the knees to keep the hip flexors relaxed.

Pro tips

  • Focus on 'closing the gap' between your ribs and your pelvis to maximize the shortening of the abdominal wall.
  • If reaching forward, imagine you are trying to touch a wall just past your feet to help keep the chest lifted.

Make it harder

  • Lift your feet 2-3 inches off the floor while maintaining the frog position to increase lower abdominal demand.
  • Extend your arms straight overhead (biceps by ears) to increase the lever length and significantly raise the intensity.

Frequently asked

What muscles does the frog crunch hold work?
The frog crunch hold primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
What equipment do you need for the frog crunch hold?
The frog crunch hold requires no equipment — just your body weight.
Is the frog crunch hold good for beginners?
The frog crunch hold is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

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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