Waist Exercise · Body Weight

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Groin Crunch

Bringing the knees out and in toward the chest during a crunch brings the hip flexors and inner thighs into what's normally a straight-line ab movement, similar to a frog crunch but with more dynamic knee movement. It's a variation worth rotating in rather than a primary ab exercise.

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Category

Waist

Equipment

Body Weight

Target

Abs

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Exercise reference published by PlanWorkouts; see our editorial standards.

How to Do the Groin Crunch

1. Lie on your back with your knees bent and feet flat on the floor.
2. Rest your hands behind your head with elbows pointed out to the sides.
3. Contract your abs to lift your legs off the floor, bringing your knees toward your chest.
4. Pause momentarily at the top, then lower your legs back down slowly.
5. Continue for the prescribed repetitions while maintaining full control through both the lift and lower phases.

Technique & Form Tips

Focus on trunk flexion, rotation, or anti-movement stability as required by your specific variation. Maintain the suggested pelvic and spinal orientation to keep tension focused on the abdominal area throughout each repetition or hold.

Common Mistakes to Avoid

• Pulling the neck: For crunch variations, avoid pulling the head forward with your hands; follow the demonstrated arm and head position.
• Lower back arching: Keep the spine controlled to prevent the lower back from hyperextending under the load.
• Excessive speed: Perform movements with deliberate control rather than relying on rapid, bouncing motions.

How to Breathe During This Exercise

Maintain a steady breathing rhythm during the effort.

Comfort and Control

Choose a load and range you can control. Stop if the movement causes pain. If discomfort persists, stop and ask a qualified professional about an appropriate exercise and range.

General guidance: Mayo Clinic on weight-training technique. Follow the specific movement steps above for this variation.

Muscles Worked

The Groin Crunch mainly targets your Abs, with your Hip Flexors helping support the movement, along with your Inner Thighs.

More Waist Exercises

3/4 Sit-Up Body Weight · Abs 45° Side Bend Body Weight · Abs Air Bike Body Weight · Abs Alternate Heel Touchers Body Weight · Abs Arm Slingers Hanging Bent Knee Legs Body Weight · Abs Arm Slingers Hanging Straight Legs Body Weight · Abs

More Abs Exercises

Arms Overhead Full Sit-Up (male) Body Weight · Abs Assisted Hanging Knee Raise Assisted · Abs Assisted Hanging Knee Raise With Throw Down Assisted · Abs Assisted Lying Leg Raise With Lateral Throw Down Assisted · Abs Assisted Lying Leg Raise With Throw Down Assisted · Abs Assisted Motion Russian Twist Medicine Ball · Abs

Equipment Alternatives

Don't have body weight? These target the same abs with different equipment.

Assisted Hanging Knee Raise Assisted · Abs Assisted Motion Russian Twist Medicine Ball · Abs Band Alternating V-Up Band · Abs Barbell Press Sit-Up Barbell · Abs

FAQ

What muscles does the Groin Crunch work?

The Groin Crunch mainly works your abs. It also helps strengthen your hip flexors and inner thighs. Using good, smooth form makes sure you work the right muscles and avoid unnecessary strain on your joints.

What equipment do I need for the Groin Crunch?

You do the Groin Crunch with no equipment — just body weight. Make sure your equipment is set up safely before starting. If you work out at home or have limited gear, check out our alternative exercises below.

What form mistake should I watch for on the Groin Crunch?

One mistake to watch for is pulling the neck: For crunch variations, avoid pulling the head forward with your hands; follow the demonstrated arm and head position.. Use a comfortable range and a controlled return; reduce the load if you cannot maintain the demonstrated setup.

How many sets and reps should I perform on the Groin Crunch?

To tone and grow muscle, do 3 to 4 sets of 10 to 15 smooth reps with 60 seconds of rest, focusing on a full stretch and squeezing the muscle at the top of each rep.

What's a good alternative to the Groin Crunch?

The Assisted Hanging Knee Raise trains your abs with assisted and a similar movement pattern. Review its form guide before substituting it, since setup and range of motion can differ.