10 Best Frog Crunch Alternatives for No-Equipment Core Training

The Frog Crunch is done lying on your back. Ranked closest by our scoring: the Knee Touch Crunch, the 3/4 Sit-up and the Flexion Leg Sit Up (Bent Knee). Five harder versions, among them the Flexion Leg Sit Up (Straight Arm) and the Reverse Crunch, are listed below as progressions rather than swaps.

Updated Ranked by our 12-factor similarity model How it works

Original Exercise: Frog Crunch

Frog CrunchPlay demonstration
Primary muscle
Abs
Equipment
Bodyweight
Difficulty
Beginner
Type
Isolation

Secondary muscles: Hip Flexors

How to perform Frog Crunch
  1. Lie flat on your back with your knees bent and feet flat on the ground.
  2. Place your hands behind your head with your elbows pointing outwards.
  3. Engaging your abs, lift your upper body off the ground, curling forward until your torso is at a 45-degree angle.
  4. Pause for a moment at the top, then slowly lower your upper body back down to the starting position.
  5. Repeat for the desired number of repetitions.
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Ranked Frog Crunch Alternatives

10 substitutes, ranked by how closely each one matches the Frog Crunch on movement pattern, muscles worked, equipment and body position. The higher the score, the less you change. Open "How to perform this exercise" on a card for the steps; every card title links to that exercise's own alternatives page. Harder versions are tagged as progressions and kept out of the top spot even when they score higher.

  1. Best match
    Knee Touch CrunchPlay demonstration

    1. Knee Touch Crunch

    99% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation

    It uses the same equipment and still works the abs.

    How to perform this exercise
    1. Lie flat on your back with your knees bent and feet flat on the ground.
    2. Place your hands behind your head with your elbows pointing outwards.
    3. Engaging your abs, lift your shoulder blades off the ground and reach your right hand towards your left knee.
    4. Return to the starting position and repeat, this time reaching your left hand towards your right knee.
    5. Continue alternating sides for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  2. 3/4 Sit-upPlay demonstration

    2. 3/4 Sit-up

    95% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation
    How to perform this exercise
    1. Lie flat on your back with your knees bent and feet flat on the ground.
    2. Place your hands behind your head with your elbows pointing outwards.
    3. Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle.
    4. Pause for a moment at the top, then slowly lower your upper body back down to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  3. Flexion Leg Sit Up (Bent Knee)Play demonstration

    3. Flexion Leg Sit Up (Bent Knee)

    95% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation
    How to perform this exercise
    1. Lie flat on your back with your knees bent and feet flat on the ground.
    2. Place your hands behind your head with your elbows pointing outwards.
    3. Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle.
    4. At the same time, lift your legs off the ground, bending your knees and bringing them towards your chest.
    5. Pause for a moment at the top, then slowly lower your upper body and legs back down to the starting position.
    6. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  4. Flexion Leg Sit Up (Straight Arm)Play demonstration

    Progression

    4. Flexion Leg Sit Up (Straight Arm)

    95% match
    • Abs
    • Bodyweight
    • Intermediate
    • Isolation

    Pick this when you want a harder version that still works the abs.

    How to perform this exercise
    1. Lie flat on your back with your legs extended and arms straight above your head.
    2. Engaging your abs, lift your upper body off the ground while simultaneously lifting your legs towards your chest.
    3. Reach your hands towards your toes as you lift your upper body and legs.
    4. Pause for a moment at the top, then slowly lower your upper body and legs back down to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 10 to 15 reps.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  5. Groin CrunchPlay demonstration

    5. Groin Crunch

    95% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation
    How to perform this exercise
    1. Lie flat on your back with your knees bent and feet flat on the ground.
    2. Place your hands behind your head with your elbows pointing outwards.
    3. Engaging your abs, lift your legs off the ground, bringing your knees towards your chest.
    4. Pause for a moment at the top, then slowly lower your legs back down to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  6. Stability Ball Crunch (Full Range Hands Behind Head)Play demonstration

    6. Stability Ball Crunch (Full Range Hands Behind Head)

    92% match
    • Abs
    • Stability-ball
    • Beginner
    • Isolation

    A good swap when you have a stability ball to work with, and it still works the abs.

    How to perform this exercise
    1. Sit on the stability ball with your feet flat on the ground and your knees bent at a 90-degree angle.
    2. Place your hands behind your head with your elbows pointing outwards.
    3. Engaging your abs, slowly curl your upper body forward, bringing your chest towards your knees.
    4. Pause for a moment at the top, then slowly lower your upper body back to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
    • Balance: harder to stay steady on than the Frog Crunch
  7. Reverse CrunchPlay demonstration

    Progression

    7. Reverse Crunch

    89% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation
    How to perform this exercise
    1. Lie flat on your back with your arms extended along your sides.
    2. Bend your knees and lift your feet off the ground, bringing your thighs perpendicular to the floor.
    3. Contract your abs and curl your hips off the floor, bringing your knees towards your chest.
    4. Pause for a moment at the top, then slowly lower your hips back down to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  8. Flat Bench Leg Pull-in

    Progression

    8. Flat Bench Leg Pull-in

    89% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation
    How to perform this exercise
    1. Lie on an exercise mat or a flat bench with your legs off the end.
    2. Place your hands either under your glutes with your palms down or by the sides holding on to the bench (or with palms down by the side on an exercise mat). Also extend your legs straight out. This will be your starting position.
    3. Bend your knees and pull your upper thighs into your midsection as you breathe out. Continue this movement until your knees are near your chest. Hold the contracted position for a second.
    4. As you breathe in, slowly return to the starting position.
    5. Repeat for the recommended amount of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  9. Sit-upPlay demonstration

    Progression

    9. Sit-up

    89% match
    • Abs
    • Bodyweight
    • Beginner
    • Isolation
    How to perform this exercise
    1. Lie flat on your back with your knees bent and feet flat on the ground.
    2. Place your hands behind your head with your elbows pointing outwards.
    3. Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle.
    4. Pause for a moment at the top, then slowly lower your upper body back down to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 8 to 12 reps, and add reps before you add load.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch
  10. Lying Leg-hip RaisePlay demonstration

    Progression

    10. Lying Leg-hip Raise

    88% match
    • Abs
    • Bodyweight
    • Intermediate
    • Isolation
    How to perform this exercise
    1. Lie flat on your back with your legs extended and your arms by your sides.
    2. Place your hands under your glutes for support.
    3. Engage your core and lift your legs off the ground, raising them towards the ceiling.
    4. Pause for a moment at the top, then slowly lower your legs back down to the starting position.
    5. Repeat for the desired number of repetitions.

    Sets and reps: 3 sets of 10 to 15 reps.

    Why this matches
    • Primary muscle: abs, the same as the Frog Crunch
    • Equipment: bodyweight only, the same as the Frog Crunch
    • Body position: lying on your back, the same as the Frog Crunch

Frog Crunch FAQ

What muscles does Frog Crunch work?

Frog Crunch primarily targets the rectus abdominis while the hip flexors assist during leg positioning. The movement produces lumbar flexion, so the erector spinae must eccentrically control the return; cue: exhale and actively curl the sternum toward the pelvis to bias the rectus.

What is the best bodyweight alternative to Frog Crunch?

The reverse crunch is the best bodyweight substitute for targeting the lower rectus without heavy hip-flexor involvement. Cue: draw the pelvis up by tilting the pelvis and lifting the sacrum off the mat, avoiding momentum from swinging the legs.

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