The Best Way to Do Crunches So They Actually Work Your Abs
Whether you're a frequent or infrequent gym-goer, there's a good chance you've done crunches. Crunches are a classic core-strengthening exercise. But while they may seem ubiquitous — heck, they're even part of the dreaded Presidential Fitness Test — they aren't the only way to strengthen your abs.
Like all exercises, crunches work best — and make you the least susceptible to injury — when they're done with proper form. POPSUGAR spoke with Grace Taylor, PT, DPT at H&D Physical Therapy, to learn everything you need to know about this classic core move, including whether it's actually worth your time, how to do crunches correctly, and plenty of crunch exercise variations that work your abs in different ways.
The Benefits of Crunches
Crunches utilize and strengthen your rectus abdominis (the ab muscle along the front of your stomach), internal and external obliques (which wrap around the sides of your stomach), transverse abdominis (your deepest, corset-like ab muscle), and hip flexors, Taylor says. The muscles utilized during crunches are important stabilizing muscles in the body. Better stability means better balance, lifting, postural control, and power production, plus minimized aches and pains, particularly in the lower back. Overall, a strong core supports just about every movement you do.
And the crunch movement does show up in your everyday life — think about how you get out of bed in the morning or get up from a couch or lying on the floor. Strengthening the muscles involved in this movement pattern will help you continue to execute it safely in your day-to-day.
Crunches Form Tips
There are two common positions for your hands while performing crunches, and Taylor has a preference. You can either place your hands behind your head, or you can cross your arms over your chest.
Placing your hands behind your head creates a longer lever arm and requires more intense core work. However, with this added challenge, it's easier to use momentum, rather than strength, to complete your crunches. This can place a lot of pressure on the spinal segments in the neck and upper back. If you use this variation, ensure your arms remain inactive throughout the entire exercise, so you're not pulling on your neck.
Placing your hands on your chest makes it easier to round your midback during the crunch, which can place more pressure on your spine and decrease your core use. However, this position is less likely to strain your spine than placing your hands behind your head, which is why Taylor recommends it.
To keep good form, Taylor recommends that you avoid tucking your chin toward your chest. A good way to avoid this is by finding a spot on the ceiling to keep your eyes on. Additionally, making sure you keep your low back flush with the ground is key. Sitting up too much can put a lot of strain on your spine and hips — if your back comes off the ground, know that you've gone too far. (That move is generally considered a "sit-up" rather than a crunch.)
Also, oftentimes when crunches are done absentmindedly, your hip flexors take over and pull on your lower-back muscles, which may cause spinal issues down the road, says Glo trainer Ridge Davis. And when they take over, they disengage your abs, making the crunch exercise far less effective as a core move. "It's all about awareness when performing crunches — or any exercise for that matter," Ridge says.
How to Do Crunches
With that in mind, it's worth it to learn how to do crunches correctly. "My philosophy is that there is not a bad exercise but a poorly executed one," Davis says. For a visual, watch Pilates instructor Isa Welly do this move properly, or follow the specific steps on how to do a crunch below.
- Lie on the floor with your back flat, both knees bent, and feet planted on the floor about shoulder-width apart. Cross your arms, and place your hands on your chest.
- Inhale, then exhale and activate your core muscles to lift your shoulder blades off the ground.
- Hold for a second, then inhale while slowly lowering your shoulder blades to the floor. That's one rep.
Crunch Cautions and Modifications
Taylor confirmed what you may have already heard, that crunches are a heavily debated exercise. Like burpees, they can be beneficial if done property, but they can also put a lot of strain on your spine. Taylor doesn't recommend crunches to people with a history of neck or back pain and recommends choosing a different core exercise if you have pain during, immediately after, or the day after you do crunches. The good news? We have some ideas for you right here.
Keep reading for some crunch exercise variations that target different parts of your core and can be better choices depending on your exercise history and ability.
— Additional reporting by Lauren Mazzo and Nicole Yi
Crunch Variation: Double-Leg Stretch
This classic Pilates ab move and crunch variation is perfect for working both your upper and lower abs. The goal is to feel a deep scoop in your abs, keeping your core strong and stable, while your extremities move.
- Start lying on your back with your hips and knees bent to 90 degrees in a tabletop position. Lift your upper back and head off the mat, reaching your fingers toward your toes.
- Lengthen your legs away from your center (at about a 45-degree angle to the floor) as you lower your upper body, reaching your arms overhead. Keep your low back pressing into the floor.
- Bend your legs back into tabletop position as you lift your upper body off the floor and reach your hands toward your toes. That's one rep.
Crunch Variation: Bicycle Crunch
Bicycle crunches are a great way to target your rectus abdominis and obliques in one easy exercise. Speed is not the name of the game here; go slowly to focus on your form and breathing. Also note: it's not necessary to touch your elbows to your knees, as this could strain your neck.
- Lie flat on the floor with your lower back pressed to the ground (pull your abs down to also target your deep abs). Interlace your fingers, and put your hands behind your head.
- Bring your knees in toward your chest, and lift your shoulder blades off the ground.
- Straighten your right leg out to about a 45-degree angle to the ground while turning your upper body to the left, bringing your right elbow toward your left knee. Make sure your rib cage is moving and not just your elbows.
- Now switch sides, and do the same motion on the other side to complete one rep (and to create the "pedaling" motion).
Crunch Variation: Pilates Scissor
Another Pilates mainstay, scissors demand the same core stability as the double-leg stretch, but when extending one leg at a time.
- Lie on your back, and engage your core to lift your upper body off the floor so your shoulder blades hover.
- Lift your left leg to hover off the floor, then bring it up toward the ceiling, gently holding your right shin.
- Keep your upper body lifted as you switch legs. That's one rep.
Crunch Variation: Side-Lying Crunch
This simple — and literal — twist on the crunch exercise places more demand on your obliques, the muscles that wrap around the sides of your torso. Depending on your spinal mobility, you may not be able to place your legs flat on the floor — that's OK.
- Start lying face-up on a mat with your knees bent and your feet flat on the mat. Your heels should be about a foot away from your hips. From this position, lower both legs to the right. Your right leg should be on the ground, and your left leg should be stacked on top of the right. Your upper back and shoulders should be flat on the mat.
- With your hands behind your head or crossed in front of your chest, engage your core (gently brace your abdominal muscles) and slowly lift your shoulders off the ground, performing a crunch.
- With control, lower your body back down to the starting position. That's one rep.
- Try 10 reps on each side. Do a total of three sets.
Crunch Variation: Seated Knee Tuck
This advanced crunch variation can be a little hard on your hip flexors and lower back; if you experience any pain, stop doing this exercise and rest or try a different move.
- Start seated on the ground with your feet on the floor in front of you, knees bent. Place your hands about an inch behind your back with your fingers facing forward. Lift both feet up off of the ground, and balance on your glutes.
- Extend both legs to hover just off the floor as you simultaneously lower your upper body a few inches.
- Using your abs, bring your legs back to your chest. That's one rep.
Crunch Variation: Overhead Reach With Leg Lower
This move challenges both your lower and upper abs to maintain torso stability while your arms and legs move away from your center. If you don't have a dumbbell, you can do this move with just bodyweight, too.
- Lie on your back with your arms reaching toward the ceiling, holding one weight with both hands. With your left leg bent and right leg out long, bring your right toes toward the ceiling. This is your starting position.
- Lower your arms and leg toward the floor, keeping your lower back touching the mat.
- Lift your arms and leg to return to the starting position. That's one rep.
Crunch Variation: Cable Crunch
If you are at the gym and have a cable machine available, this weighted cable crunch is a great way to really feel the work happening in your abs.
- Attach a triceps rope handle to the pulley on the carriage of a cable station. Adjust the carriage so it's near the top third of the machine. The exact position will vary based on your height.
- Next, select the amount of resistance you want. (Start light, and you can always go heavier as you begin to become more comfortable with the movement.)
- Facing the pulley, come into a kneeling position approximately one and a half feet away from the machine.
- Grab the triceps rope handles, and brace your core. You should feel a light stretch in your abs; if not, increase the weight. Make sure your weight is in your shins.
- Simultaneously pull both handles with bent arms toward the floor to perform a crunch. Your elbows should be parallel to your thighs.
- With control, return to the starting position as you maintain tension on the pulley. That's one rep.
Crunch Variation: Reverse Crunch
Taylor says reverse crunches are one of her favorite crunch variations. Here's how to do them.
- Lying on your back, lift your legs in the air with your knees bent at about 90 degrees. Place your hands on the floor beside your hips.
- Without momentum, use your lower abs to slowly curl your hips off the floor and into your chest. Slowly lower them back to the starting position.
- That's one rep.
Crunch Variation: Pilates Roll-Down
This Pilates roll-down is essentially a sit-up in reverse. By carefully and slowly lowering yourself down one vertebra at a time, you can improve your spinal mobility as well as the strength of your core in every position.
- Start sitting on your mat, with your knees bent and legs parallel with feet flat on the floor. Reach your arms toward the ceiling to lengthen your spine.
- Exhale and pull your abs deeply toward your spine, and begin to roll down the floor one vertebra at a time; the movement should be smooth and controlled. Once your head reaches the mat, reach your arms overhead so they're parallel to the floor.
- Exhale and begin to roll up, peeling your spine off the mat and coming all the way to sitting. Inhale your arms up toward the ceiling. That's one rep.
Crunch Variation: Butterfly Crunch
This crunch and reverse-crunch hybrid works both your upper and lower abs.
- Lie on your back with your knees open and the soles of your feet together (in a butterfly position). Lengthen your arms overhead so they're resting on the floor.
- Exhale and bring your hands and knees toward each other, performing a full-body crunch: lift your shoulder blades and hips just slightly off the mat. Hold this position for a moment, engaging your abs.
- Slowly lower your arms and legs back to starting position. That's one rep.
Crunch Variation: V Crunch
This V-crunch variation combines a crunch with a leg raise so you stretch (and strengthen) your entire core. Because your arms and legs create very long levers, this is a more challenging crunch variation.
- Lie on your back, with your arms and legs extended toward the ceiling.
- Inhale and lower your legs toward the floor while reaching your arms overhead, keeping your shoulders off the mat and lower back pressed into the mat.
- Squeeze your abs, and exhale to draw your arms and legs together and lift your upper back off the floor, reaching your hands toward your feet.
- That's one rep.
Crunch Variation: Pilates Ball Ab Curl
Grab a Pilates ball for this crunch variation. It uses a very small movement, but you'll still feel it in your abs, promise.
- Start sitting on a mat with a Pilates ball behind your back, just below your ribs. Then lean back, so your torso is almost parallel to the floor. Place your hands behind your head, keeping your elbows wide.
- Exhale, pulling your abs to your spine while pressing your low ribs into the ball to perform a curl. The movement is small but concentrated.
- Inhale, and lower your chest without arching your back. That's one rep.
Crunch Variation: Crunch on Exercise Ball
If you have one, try this crunch on an exercise ball.
- Sit on a well-inflated exercise ball. Place your hands behind your head, and walk your feet away from the ball so your torso starts to roll onto the ball. The ball should support your hips and the curve of your lower back. Your legs should form a bridge with your knees bent at right angles.
- Exhale and lift your upper body by about 45 degrees, pulling your deep abs in toward your spine.
- Hold for one second, then lower your shoulders to return to starting position. That's one rep.
Crunch Variation: Toe Touch Double With Medicine Ball
Use a medicine ball to add weight and challenge to this crunch variation.
- Begin lying on your back with your legs extended toward the ceiling, holding the medicine ball over your chest.
- Engage your abs to press your lower back into the mat. Exhale and lift your head, neck, upper back, and hips just off the mat, crunching your arms and legs together and up toward the ceiling.
- Inhale, and lower your hips and upper back to the floor. That's one rep.