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Exercises

Reverse crunch alternatives: lower-ab swaps for the floor, the bar and the cable

Published October 23, 2026

The best reverse crunch alternative is the lying knee raise: the same knees-to-chest motion, finished with a small hip curl, from flat on the floor. If your lower back lifts or your hip flexors take over, the dead bug trains the same abs with your back pinned down. With a pull-up bar or captain's chair, hanging knee raises make it harder; once those are easy, move to hanging leg raises, and for loaded ab work use the cable crunch.

What a reverse crunch alternative has to replace

The reverse crunch trains your abs by curling your hips and pelvis up toward your ribs, the opposite end of a normal crunch. The work happens in the last few inches, when your hips peel off the floor; just swinging your knees toward your chest is mostly hip flexors. A replacement has to keep that curl of the pelvis, or train the abs to hold your lower back still.

How to do the reverse crunch

On the floor, no equipment

Start with the easiest that you can do with your lower back staying down, and take each set within a rep or two of failure.

Closest swap, on the floor

Lying Knee Raise

Abs

You lie flat, draw your knees toward your chest and finish with a small curl of the hips, which is the same motion as a reverse crunch with the legs starting long. Start here if reverse crunches feel awkward.

How to do it

  1. Lie face up on the floor or a flat bench, legs long, and hold the floor beside your hips or the bench behind your head.
  2. Lift your heels a few inches and press your lower back down.
  3. Draw your knees toward your chest and let your hips curl up slightly at the end.
  4. Push your legs back out to a hover over two seconds and repeat.

Cues

  • Curl the hips at the top
  • Slow on the way out
  • Heels hover between reps

Common mistakes

  • Stopping when the thighs are vertical: finish with the small hip curl.
  • Letting the legs drop fast: the slow return is half the work.
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Easier, one leg at a time

Alternating Leg Raise

Abs

Scissoring one straight leg up while the other hovers keeps your abs working to hold your lower back flat. Easier than lifting both legs, so it suits beginners.

How to do it

  1. Lie face up with your legs long and your hands behind your head.
  2. Flatten your lower back and lift both heels just off the floor.
  3. Raise one straight leg until it points up while the other leg hovers.
  4. Swap legs in a slow scissor, never letting either heel rest.

Cues

  • Lower back stays down
  • Slow scissor
  • Hover leg higher if needed

Common mistakes

  • Arching when the low leg drops: raise the hover height.
  • Bending the knees a lot: keep them nearly straight.
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Lower back stays on the floor

Dead Bug

Abs

You reach opposite arm and leg away while your lower back stays pressed down. It trains your abs to keep your pelvis still, which fixes the lower-back arch many people get on reverse crunches.

How to do it

  1. Lie face up on a mat, arms straight up over your shoulders and knees bent 90 degrees directly above your hips.
  2. Breathe out fully and tilt your pelvis slightly so your lower back presses flat into the floor; keep it there for the whole set.
  3. Reach your right arm back toward the floor behind your head and straighten your left leg out toward the floor at the same time.
  4. Stop when your arm and leg hover just above the floor, or sooner if your lower back starts to lift.
  5. Bring both back to the start, then repeat on the opposite pair. One rep is one side.

Cues

  • Lower back glued to the floor
  • Exhale as you reach
  • Slow is the exercise

Common mistakes

  • Letting the lower back arch as the leg goes out: shorten the reach, keep the knee bent more, or lower only the leg until you can hold the position.
  • Rushing through the reps: take two or three seconds to reach out and the same to come back; speed lets momentum do the work your abs should do.
  • Holding your breath: breathe out as you reach and in as you return, so you learn to brace while breathing.
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Upper-ab partner on the floor

Crunch

Abs

The normal crunch curls your ribs toward your hips, the other end of the same muscle. Pair it with any lower-ab swap for a full floor session.

How to do it

  1. Lie on your back, knees bent, feet flat and arms reaching forward at shoulder height.
  2. Breathe out and curl your head and shoulders up until the shoulder blades clear the mat, ribs moving toward your hips.
  3. Pause for a second when your shoulder blades are just off the floor.
  4. Uncurl slowly until your shoulders touch down, then start the next rep.

Cues

  • Ribs to hips
  • Exhale up
  • Chin off chest

Common mistakes

  • Reaching with the arms only: lift your shoulder blades with your abs and let the arms follow.
  • Bouncing off the floor: lower under control so every rep starts from rest.
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Both ends at once, no equipment

Jackknife

Abs

Arms and legs rise together until you fold into a V. It is harder than a reverse crunch, so use it when the floor moves get easy.

How to do it

  1. Lie flat with your legs long and your arms resting along your sides.
  2. Brace and lift your shoulders and straight legs off the floor together, arms reaching forward.
  3. Reach your fingertips toward your toes so you fold into a V.
  4. Lower both ends back to a light touch on the floor over two seconds, then repeat.

Cues

  • Fold, then unfold slowly
  • Arms and legs meet over the hips
  • No bounce at the bottom

Common mistakes

  • Throwing the arms to get up: lift your chest with your abs and let the arms just follow.
  • Crashing back to the floor: lowering is half the rep.
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Pull-up bar, captain's chair and bench

Your legs hang below you, so these get hard fast. Curl your hips at the top of every rep, or it turns into a hip flexor exercise.

Harder swap on a pull-up bar

Hanging Knee Raise

Abs

Hanging from a bar, you raise your knees and curl your hips up. Your body weight hangs below you, so each rep is harder than on the floor.

How to do it

  1. Take hold of the bar with an overhand grip about shoulder-width apart and hang with your arms straight and your feet clear of the floor.
  2. Pull your shoulders slightly down away from your ears and let your body go still before the first rep.
  3. Bend your knees and bring them toward your chest, keeping your legs together.
  4. As your thighs pass parallel to the floor, tuck your tailbone and roll your hips up so your knees climb toward your chest.
  5. Lower your legs slowly until they hang straight below you again, and stop any swing before the next rep.

Cues

  • Roll the hips, don't just lift the knees
  • Lower slower than you lift
  • Start each rep from stillness

Common mistakes

  • Swinging back and forth to get the knees up: pause at the bottom of each rep, and if you can't stop the swing, shorten the set.
  • Stopping when the thighs reach parallel: that is mostly hip flexors; keep going and curl the pelvis up so the abs finish the rep.
  • Letting go of the shoulders and hanging loosely: keep a little tension pulling the shoulders down so you stay steady on the bar.
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Knee raise with your back supported

Captain's Chair Knee Raise

Abs

Forearms on the pads and back against the pad, you bring your knees up and curl your hips forward. Your grip never runs out, so your abs decide when the set ends.

How to do it

  1. Step onto the platform, set your forearms on the pads, grip the handles and press your back into the back pad.
  2. Step off so your legs hang straight below you.
  3. Raise your knees until your thighs pass level with your hips, then curl your hips forward a little at the top.
  4. Lower your legs until they hang straight again without swinging, then repeat.

Cues

  • Shoulders down, away from your ears
  • Curl the hips at the top
  • Dead stop at the bottom

Common mistakes

  • Dropping the legs fast: lower over two seconds, since the way down works your abs too.
  • Swinging into the next rep: pause with straight legs before every lift.
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Hardest swap on a bar

Hanging Leg Raise

Abs

The hanging knee raise with straight legs, which makes the lever much longer. Move to it once you can do 15 clean hanging knee raises.

How to do it

  1. Take an overhand grip on the bar and hang with straight arms and your feet together.
  2. Pull your shoulders down slightly and stop any swing.
  3. Raise your legs with soft knees until they are at least level with your hips, letting your pelvis tilt up at the top.
  4. Lower them slowly to a still hang and repeat.

Cues

  • Still hang before every rep
  • Pelvis tilts up at the top
  • Bend the knees to scale

Common mistakes

  • Swinging the legs up with momentum: pause at the bottom of every rep.
  • Lifting only to hip height with an arched back: if the pelvis never tilts, bend the knees more.
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Advanced swap on a bench

Dragon Flag

Abs

Holding a bench behind your head, you lower your straight body from vertical with only your upper back down. Very hard; start with lowering only, a few reps at a time.

How to do it

  1. Lie face up on a bench and grip it behind your head with both hands.
  2. Roll your hips and legs up until your body points toward the ceiling, resting on your upper back.
  3. Lower your straight body slowly toward the bench, keeping your hips in line with your shoulders.
  4. Stop just above the bench and raise back to vertical, or lower only and roll back up with bent knees.

Cues

  • Straight line from shoulders to toes
  • Lower as slowly as you can
  • Hips never bend

Common mistakes

  • Bending at the hips as you lower: tuck your knees until you can stay straight.
  • Letting your lower back arch: stop the set there.
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Cables, machines and the ab wheel

When you want to add weight to your ab work and track it like any other lift.

Loaded swap with a cable

Cable Crunch

Abs

Standing under a high cable, you crunch your ribs toward your hips. You can add weight in small steps, which the reverse crunch can't do.

How to do it

  1. Attach a rope to a high pulley, pick a moderate weight, and hold one end of the rope in each hand beside your head or at your upper chest.
  2. Turn your back to the stack, take a step forward so the weight lifts off, and set your feet hip-width apart with soft knees.
  3. Keep your hands fixed next to your head and breathe out as you curl your ribs down toward your hips, rounding your upper and middle back.
  4. Squeeze at the bottom for a second, with your elbows heading toward your thighs and your hips still in the same place.
  5. Uncurl slowly back to tall, letting the cable stretch your abs, then start the next rep without resting the stack.

Cues

  • Ribs to hips
  • Hips stay put
  • Round down, not bow forward

Common mistakes

  • Hinging at the hips: if your butt moves back as you go down, your hip flexors and arms take over; lock your hips in place and only round your spine.
  • Pulling with the arms: keep your hands glued to your head so the rope moves only because your torso curls.
  • Going too heavy: if you cannot pause at the bottom, the weight is too much; the abs need control, not a yank.
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Loaded swap on a machine

Machine Crunch

Abs

The seated ab machine lets you load a crunch with a pin, so you can train your abs in a set rep range like any other muscle and see the weight go up.

How to do it

  1. Set the seat height so the machine's pivot sits near your belly button and your feet hook under the pads or rest on the footplate.
  2. Hold the handles or place your arms on the pads with your elbows pointing forward, and sit tall with your back on the pad.
  3. Breathe out and curl your chest down toward your hips by rounding your spine, keeping your hips on the seat.
  4. Hold the squeeze for a second when your ribs are closest to your pelvis.
  5. Uncurl slowly back to upright and let the weight touch down lightly before the next rep.

Cues

  • Ribs to hips
  • Arms just hold on
  • Slow on the way back

Common mistakes

  • Pulling with your arms: if your shoulders and arms burn first, lower the weight and let your hands rest on the handles.
  • Hinging at the hips instead of curling: keep your lower back on the pad and think about shortening the distance from your ribs to your pelvis.
  • Bouncing the stack between reps: pause briefly at the top so the abs start every rep from a stop.
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Whole-ab swap with a wheel

Ab Wheel Rollout

Abs

Rolling a wheel out from your knees makes your abs fight to stop your lower back from sagging. A hard, short-range set that works the whole front of your trunk.

How to do it

  1. Kneel on a pad with the wheel under your shoulders and arms straight.
  2. Tuck your pelvis so your lower back rounds slightly, then roll the wheel forward as your hips follow.
  3. Go as far as you can while keeping that tuck, ideally until your arms are near overhead.
  4. Pull the wheel back to your knees by squeezing your abs, not by sitting your hips back.

Cues

  • Tuck first, then roll
  • Hips move with the wheel
  • Stop before the back arches

Common mistakes

  • Letting the lower back sag at the far end: roll toward a wall so it stops you at a range you control.
  • Pulling back by bending at the hips: drag the wheel back with your abs and keep the hips forward.
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Example sessions without the reverse crunch

Session 1

Gym, want ab work you can load

Open in the session builder
  • Workouts3× a week
  • Working sets30 a week
  • Per workout~20 min
  • EquipmentAdjustable Cable, Pull-Up Bar, Ab Wheel

You train in a gym, reverse crunches have stopped feeling like much, and you want ab work that progresses like your other lifts.

The cable crunch leads because you can add weight to it, hanging knee raises take the reverse crunch's place for the lower abs, and ab wheel rollouts finish with the whole trunk. 10 working sets.

Abs
ExerciseSets × repsRIRRest
Cable CrunchRibs to hips, hips stay still. 4 × 10–15 1 75 s
Hanging Knee RaiseCurl the hips at the top. 3 × 8–15 1 75 s
Ab Wheel Rollout 3 × 6–12 2 75 s
How to run it
Two or three times a week at the end of any session.
How to progress
On the cable crunch, add the smallest weight jump when every set reaches the top of its range. On knee raises and rollouts, add reps, then move to hanging leg raises or longer rollouts.
Open in the session builder

Session 2

Home, floor only

Open in the session builder
  • Workouts3× a week
  • Working sets33 a week
  • Per workout~20 min
  • EquipmentBodyweight

You train at home with a mat and nothing else.

Lying knee raises take the reverse crunch's place, dead bugs keep your lower back down, crunches cover the upper end of the abs and jackknives finish. Bodyweight is light, so sets run long and close to failure with short rest. 11 working sets.

Abs
ExerciseSets × repsRIRRest
Lying Knee Raise 3 × 12–20 1 45 s
Dead BugReps are per side. 3 × 8–12 2 45 s
Crunch 3 × 15–25 1 45 s
Jackknife 2 × 8–15 1 45 s
How to run it
Three times a week, on its own or after another workout. Lower every rep slowly.
How to progress
Add reps to the top of each range, then slow the lowering to three seconds, then move to the next harder move in the floor section.
Open in the session builder

Session 3

Reverse crunches feel easy

Open in the session builder
  • Workouts2× a week
  • Working sets20 a week
  • Per workout~25 min
  • EquipmentPull-Up Bar, Ab Crunch Machine

You can do 20 clean reverse crunches and train in a gym with a pull-up bar, a flat bench and an ab crunch machine.

Hanging leg raises and dragon flags are two of the hardest lower-ab moves there are, done for low reps with full rest, and the machine crunch adds loaded work for the rest of the abs. 10 working sets.

Abs
ExerciseSets × repsRIRRest
Hanging Leg RaiseNo swinging between reps. 4 × 6–10 2 90 s
Dragon FlagLower over three seconds. 3 × 3–6 2 2 min
Machine Crunch 3 × 10–15 1 1 min
How to run it
Twice a week, at the start of a session while you are fresh, since these are hard to do well tired.
How to progress
Add one rep per set each week to the top of the range. On dragon flags, lower more slowly before you add reps.
Open in the session builder

Make it fit you

Questions

What can I do instead of reverse crunches?

Lying knee raises are the closest. Dead bugs are easier on your lower back, hanging knee and leg raises are harder, and cable crunches let you add weight.

How do you modify a reverse crunch?

To make it easier, keep your knees bent and only lift your hips an inch. To make it harder, start with your legs straighter, do it on an incline bench, or move to hanging knee raises.

What muscles does the reverse crunch work?

Mainly your abs (rectus abdominis), with your obliques helping. Your hip flexors work too, more if you swing your legs instead of curling your hips.

What is the best exercise for lower abs?

Your abs are one muscle, but hip-curling moves like the hanging knee raise, hanging leg raise and reverse crunch stress the lower part most. Pick the hardest one you can do with clean reps.

Is the reverse crunch better than a regular crunch?

Neither is better; they work the same muscle from opposite ends. Doing one of each in a session covers your abs well.