What's a good beginner rep range for the frog crunch?

Two sets of 12 to 15 reps is plenty to start, with a brief pause at the top of each one. Progress by adding a third set before you look to add any extra load, since this variation is meant to isolate the abs rather than build raw strength.

How can I make the frog crunch easier or harder?

To make it easier, keep the knees slightly bent and closer together, which reduces the hip opening you need. To make it harder, hold a light plate or dumbbell against your chest as you crunch, or extend the pause at the top of each rep.

What is the frog crunch good for, and who might want to skip it?

It is a beginner-friendly way to feel the rectus abdominis work without the hip flexors taking over, which makes it a good teaching drill before harder crunch variations. It is a poor fit if your hips or groin are irritated by the wide-open knee position, since holding that stance for reps can aggravate hip discomfort.

Beginner

Frog Crunch

The frog crunch places the soles of the feet together and lets the knees fall wide, which quiets the hip flexors and rectus femoris so the abs do more of the crunching. From that butterfly leg position you curl the ribs toward the pelvis and reach past the knees. It is a beginner-friendly way to feel the rectus abdominis work in isolation.

Equipment: Body Weight
Body part: Abs
Type: Strength
Browse by muscle: Upper Rectus Abdominals
Browse by movement: Spinal Flexion

How to do it

1
Lie on your back and bring the soles of your feet together, letting the knees drop open.
2
Extend the arms toward your feet and brace the abs.
3
Exhale and crunch the shoulder blades up, reaching the hands past the knees.
4
Squeeze the abs at the top of the crunch.
5
Inhale and lower the shoulders back under control.
6
Keep the feet together and the knees relaxed and open throughout.

Tips

Let the knees stay wide so the hip flexors cannot assist the crunch.
Curl the spine to lift the shoulders rather than pulling on the neck.
Pause briefly at the top to make the abs work through the whole range.

Variations

Common mistakes

The feet drift apart at the soles instead of staying pressed together, losing the hip position that keeps this variation different from a standard crunch.
The hands grab for the feet instead of reaching only past the knees, pulling the body into a longer curl than the frog position calls for.
Bouncing out of the bottom position skips the brief reset the exercise needs between reps, so momentum starts replacing the crunch.
The pace speeds up once the shoulders start to fatigue, trading full reps for quick, shallow ones near the end of the set.
The lower back lifts off the floor at the top of the crunch instead of staying grounded, arching instead of curling through the spine.

Frequently asked

What's a good beginner rep range for the frog crunch?: Two sets of 12 to 15 reps is plenty to start, with a brief pause at the top of each one. Progress by adding a third set before you look to add any extra load, since this variation is meant to isolate the abs rather than build raw strength.
How can I make the frog crunch easier or harder?: To make it easier, keep the knees slightly bent and closer together, which reduces the hip opening you need. To make it harder, hold a light plate or dumbbell against your chest as you crunch, or extend the pause at the top of each rep.
What is the frog crunch good for, and who might want to skip it?: It is a beginner-friendly way to feel the rectus abdominis work without the hip flexors taking over, which makes it a good teaching drill before harder crunch variations. It is a poor fit if your hips or groin are irritated by the wide-open knee position, since holding that stance for reps can aggravate hip discomfort.

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