The reverse crunch is an abdominal exercise that strengthens your lower core and works the rectus abdominis (aka the muscles responsible for six-pack abs). This basic move is effective on its own, or you can try variations of the exercise to work your entire core.
Unlike the traditional crunch in which you lift your shoulders off the ground, with the reverse crunch you literally do the reverse, using your lower abdominal muscles to lift your hips off the ground. "The reverse crunch is great for improving midsection core strength and stability," Grayson Wickham, DPT, physical therapist and founder of Movement Vault, says.
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Read on to learn more about how to do the reverse crunch, muscles worked, benefits, form tips and variations.
- What is the reverse crunch? The reverse crunch is an abdominal exercise in which you use your core muscles to lift your hips and lower back off the ground.
- What muscles does the reverse crunch work? "The reverse crunch primarily works the rectus abdominis," Wickham says, referring to the technical name of the "six-pack" muscle that runs along the front of your midsection. It also works your obliques and your transverse abdominis (another deep core muscle).
- Who can do it? The reverse crunch is relatively easy to perform and suitable for beginners, as well as those at an advanced fitness level, Wickham says. However, those who are pregnant or have recent injuries should stay away from this exercise.
- Is the reverse crunch bad for your back? No; in fact, reverse crunches strengthen your core muscles to help support your back and prevent injuries. It works the lower core muscles, the transverse abdominis, which can be hard to isolate. And because it doesn't require as much spinal flexion as a regular crunch, it can be less stressful on your spinal discs.
How to Do the Reverse Crunch
- Lie on the floor with your knees bent and your feet flat on the floor.
- Place your arms straight out along the side of your body with your palms down.
- Tighten your core as you lift your legs off the ground with your knees bent at 90 degrees.
- Continue moving your knees up as you contract your abs and lift your hips and lower back off of the mat.
- You can lightly push with your hands to help keep your body stable, but focus on letting your core do the work of lifting your hips up.
- Pause at the top before slowly lowering your feet back down to the starting position.
- Tap the ground with your feet (try not to rest them down) before repeating the motion.
Tip
You can also place your hands under your lower back for more support as needed.
4 Benefits of the Reverse Crunch
1. Strengthens Your Core
This exercise strengthens the muscles that make up your core, including your rectus abdominis and the deeper transverse abdomnis. It also strengthens your oblique muscles, however, it doesn't work them as much as other exercises, such as the side plank.
The great thing about strengthening your core? It can benefit other parts of your body. Core-strengthening exercises have been found to decrease pain and improve movement in those with low back pain, as found in a November 2021 study in BMC Musculoskeletal Disorders.
2. Works Your Hip Muscles
With this exercise, the majority of the movement is from the contraction of your abdominal muscles. But the reverse crunch also strengthens your hip flexors. Stronger hip flexors can improve your balance and even reduce back pain, according to a 2020 study in The Tohoku Journal of Experimental Medicine.
3. Puts Less Stress on Your Neck and Spine
Traditional crunches can put undue stress on your neck and back, while the reverse crunch keeps you more supported through the movement. This exercise also involves less spinal flexion, which puts less stress on the discs in your spine.
4. Requires No Equipment
This bodyweight exercise requires no equipment and doesn't need a lot of space, so it's easy to knock out a few sets throughout the day.
Reverse Crunch Form Tips
Don’t Arch Your Back Too Much
The reverse crunch is a relatively small motion. Only your hips or tailbone and lower back should come off the floor. Your head, shoulders and middle back should all stay glued to the ground.
Arching your back too much can put too much strain on the muscles in the area, Wickham says, which can result in pain or injury. Think about pulling your pelvis up and back toward your rib cage.
Stay Slow and Controlled
"Focus on slow and controlled movement," Wickham says. "When you perform this exercise too quickly and use too much momentum, you reduce the difficulty of the exercise and risk potential low back injury."
Your muscles may start to shake as you do the exercise — but that's not necessarily a bad sign. It just means your muscles are working hard.
Work From Your Core
Even though your hip flexors will assist some in the movement, along with your hands pressing on the floor, the majority of the exercise should come from your core. Focus on using your abdominals to lift your hips off of the mat. Keeping the motion slow and controlled will help you isolate the exercise to your abdominals.
Tip
You will feel your abdominals working, however you should not feel any pain during this movement. If you have pain, stop the exercise. It is always a good idea to get clearance from a doctor before starting a new exercise program.
3 Reverse Crunch Variations
1. Toe Taps
- Lie on your back with your knees bent, feet flat on the floor.
- Lift both legs up so that they are bent at 90 degrees. Keep your knees over your hips at all times.
- Point your toes and slowly lower your right leg down on the ground until it taps the ground, keeping the bend in your knee.
- Return to the starting position.
- Repeat on the other side.
- Perform 20 toe taps on each side.
Tip
As you do this modified reverse crunch, make sure to keep your abdominals tight and your lower back and hips on the floor at all times.
2. Weighted Reverse Crunch
- Lie on your back with your knees bent and your feet flat on the ground.
- Hold a weight over your shoulders, behind your head, arms straight.
- Tighten your core as you lift your legs off the ground with your knees bent at 90 degrees.
- Continue moving your knees up as you contract your abs and lift your hips and lower back off of the mat.
- Pause at the top before slowly lowering your feet back down to the starting position.
- Tap the ground with your feet (try not to rest them on the floor) before repeating the motion.
3. Reverse Crunch With Oblique Twist
- Lie on the floor with your knees bent and your feet flat on the floor.
- Place your arms straight out along the side of your body, palms down.
- Tighten your core as you lift your legs off the ground with your knees bent at 90 degrees.
- Continue moving as you twist your knees slightly to the left, moving them toward your left shoulder.
- As you twist, use your abdominals to lift your tailbone and lower back off of the floor.
- Pause at the top before slowly lowering your feet back down to the starting position.
- Tap the ground with your feet (try not to rest them down) before repeating the motion, twisting slightly to the right.
Can the Reverse Crunch Build Muscle for Six-Pack Abs?
Reverse crunches can definitely help you build muscle and a stronger core, Wickham says. But it takes more than just one exercise to build six-pack abs.
“Building muscle and achieving abs are essentially the same thing. You can have extremely strong abs and large abdominal muscles, but if you have a large layer of fat on top of those abs, they will not be very visible,” he says.
The reverse crunch does work the rectus abominis, which is the muscle responsible for the six-pack abs look. In order for those muscles to be visible, you need a healthy diet and a consistent cardio routine. When doing ab exercises, try to focus on doing a fairly high number of reps, such as 3 sets of 10 to 15 reps to see results. If you feel any pain or stomach cramps, it's best to take a pause from the exercise.
- Strength and Conditioning Journal: "Abdominal Crunches Are/Are Not a Safe and Effective Exercise"
- BMC Musculoskeletal Disorders: "Effects of Core Stabilization Exercise and Strengthening Exercise on Proprioception, Balance, Muscle Thickness and Pain Related Outcomes in Patients With Subacute Nonspecific Low Back Pain: A Randomized Controlled Trial"
- The Tohoku Journal of Experimental Medicine: "Core Stability and Hip Exercises Improve Physical Function and Activity in Patients with Non-Specific Low Back Pain: A Randomized Controlled Trial"