Why Crunches are the WORST Exercise After a Baby


Mummy-Tummy: The dreaded flab that anyone who’s birthed a baby is all too familiar with. As a mom of two, I understand the drive to tone that tummy and start the long process to slim-down. 

But as a fitness professional, I can tell you that the typical six weeks postpartum, even 12 or 16, is often not enough time for most women’s abdominals to be recovered enough for most exercises. And if that’s you, you could be doing more damage than good. 

Diastasis Recti

During pregnancy, the abdominal wall stretches to allow room for the uterus and baby to grow. But it takes some time for the rectus abdominis (commonly thought of as the “six pack” muscle) to heal and shrink back together. Diastasis recti literally means a separation of the rectus abdominis. 

This image comes from the website Fit2B where you also can find a video on how to check if you have diastasis recti. The Wellness Mama also has a great article on diastasis recti.

How to check if you have it:

If you are pregnant, especially in your third trimester, you probably have diastasis recti. And that’s fine. It’s normal. If you are postpartum, you likely have it to a degree. And many women go years and years frustrated with their flabby tummy without knowing their abdominal muscles are still separated, and that’s likely the cause of their “mummy tummy.”

Oh Baby! Fitness explains how to check yourself for abdominal separation

Begin by lying on the floor in a traditional sit-up position, knees bent, with your feet flat on floor.

Perform a small crunch; this will engage the rectus abdominals.

Run your fingers laterally across your stomach, feeling for a ditch running vertically down the middle of their stomach. Check both above and below the belly button.

Feel for a ditch that will feel soft, with hard (engaged) abdominals on either side. You will want to see how many fingertips you can fit laterally into the ditch.

1-2 fingertips is considered normal, 3+ should be referred to a doctor or physical therapist postpartum.

What to do about it:

Again, if you’re pregnant, don’t stress. It’s normal. If you’re less than 6 weeks postpartum, it’s never too early to do kegels! And those will go a long way to heal all kinds of issues.

Any other mamas pee when sneezing? Kegels. Do all the kegels. 

If you’ve been cleared by your doctor to resume exercise, there are four steps you can take to know when your abs are strong enough to resume normal ab exercises. Do each step while continually holding the previous steps. Only proceed to the next step when you’re able to hold all the previous steps simultaneously for 60 seconds.

Laying flat on your back with knees up, hold a kegel.

Add on: hollow out abs, as if drawing your belly button into the floor.

Add on: roll-up half-way, as if doing a partial crunch.

Add on: once you can do all these exercises in this order and simultaneously, you are ready for more advanced core work that will help to heal the separation. Make sure you hold a kegel and keep your abs hollowed out while doing other ab exercises. This video by celebrity trainer Heidi Powell gives some great examples. She also explains how to check for diastasis recti, and you can literally see her separation, which can be helpful to visualize if you’ve never checked yours before.

What NOT to do about it:

Crunches. Sit-Ups. Bicycles. Any exercise that targets obliques (the area from your armpits to your hips) or movement without proper muscular engagement will further the gap in your rectus abdominis. And don’t forget about functional movements! How do you get out of bed? Do you sit straight up and swing your legs over? That’s a sit-up. How do you check on your baby in the car? Do you twist around to make googly-eyes when stopped at a light? That works your obliques. 

Be mindful about how your body moves during daily activities. Those can almost be more damaging than 20 minutes of crunches! 

So, avoid anything that twists your upper body, shortens the distance between your shoulders and hips, and brings together your shoulder with the opposite hip (like a bicycle). Those movements put more strain on diastasis recti and should be avoided until healing is complete. 

Why this is important:

If you have diastasis recti postpartum, have you noticed how a vertical pooch pops up when you do a sit up? That’s your intestines pushing out through the separation in your muscle wall. As gross as that is, it’s usually not dangerous, except in rare cases. It can also cause low back pain when the abdominals are weak. So, this is an important issue to pay attention to, and it’s not just about vanity!

Another helpful thing to remember is you can’t target fat loss. The only thing that will burn fat is cardiovascular exercise, or doing something that gets your heart rate up and gets you sweating. But you CAN “target tone.” And the more muscle you have, the higher your metabolism will be, and the faster you’ll lose fat. But that doesn’t always correlate with weight loss. So if you don’t see the scale moving very fast, take heart. It took 9 months to gain the weight, so it’s fair to expect to take 9 months (or more!) to lose it. And if you’re like me, you probably gained at least half in the last 3 months of pregnancy and will lose it las,t too. 

So, if your “mummy-tummy” is flabbier than you’d like, diastasis recti is likely to blame. But following these four steps will set you well on your way to postpartum healing! 

Have any further questions? I’m a certified pre/postnatal personal trainer, so just ask! If I don’t have an answer, I’d love to connect you with someone who does! 

Want to know more about diastasis recti? Oh Baby! Fitness is a great resource and I also love this article from celebrity trainer Heidi Powell and Wellness Mama

Funny, but oh so very true!
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Amie Glazier
Originally from Denver, Amie enjoyed a break from cold winters while stationed in various southern locales with her husband, who is a pilot in the Navy. But they currently live outside Seattle, and she is now learning to love the rain. Amie and her husband have four small children who eat dinosaur chicken nuggets like they're going extinct and love all things aviation. After graduating with her B.A. in English, Amie worked in various fields with each military move, but never stopped writing. She has been a contributor for The Military Mom Collective since it was founded and finds joy in helping other moms connect in community. When she’s not writing or herding her adorable brood, you can find Amie working out at the local cross fit gym, binge-watching Hallmark movies, and actually enjoying chemistry while home-brewing with her husband. Amie is proud to be co-owner and Director of Partnerships for MilMC to help military families connect worldwide. You can contact Amie at info {at} militarymomcollective {dot} com and follow her journey on Instagram @mrs.amielou


  1. THANK YOU for posting about this!! I had two little girls and my body was super forgiving… and then seven years later I had a little boy (six months ago!) and I’m all out of whack! For a person well-versed in fitness and diet, it’s unearthing. I’ve progressed from four inches to two using the exercises I learned here in my six-month journey so far. And my doc is super proud 🙂

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