Trying to figure out if crunches are ok to do when you have abdominal separation can be pretty confusing, but don't worry, I'm going to break it down for you.
I classify crunches as an advanced exercise if you have diastasis recti.
Doing them too soon can make your diastasis worse, especially if you're still in the early stages of healing.
Unfortunately, this is one of the biggest mistakes I see with moms who've jumped back into fitness classes or mummy bootcamp type classes before their bodies are ready.
Before you even think about doing crunches, you need to be able to control the pressure in your core, so you aren't pushing out on your weakened connective tissue in the middle of your abs (This connective tissue is called the Linea Alba).
If you want to see what pushing out onto your diastasis looks like, you can check out this post on bulging and doming in your core.
If you want to do crunches again, you need to start by learning how to load your core and pelvic floor so you don't cause more damage to your Linea Alba.
Do you need to do crunches?
I know crunches are popular in fitness classes. In fact, I used to be a crunch and sit up queen myself back in the days when I wore neon G-string leotards over tights to teach my classes. (You can laugh all you want, but it was super fashionable in the early ’90s ).
It used to be that 5 minutes of sit-ups, crunch variations for that burn-y feeling in your abs was seen as the best and most effective training to strengthen your core and flatten your stomach.
People would actually complain if I didn’t do crunches at the end of a class because then they “hadn’t worked their Abs.”
These days I only teach crunches occasionally. I almost never programme them for my clients either.
Because I don't think they're the best or most effective exercise for core strength.
Here's why: Crunches and sit-ups mostly work the front of your abs (the Rectus Abdominals) these are the muscles that you can see on people with 6 pack abs and where you have your "gap" when you have abdominal separation.
The 6 pack muscles are really just the outer layer of your core and are used to pull your body forwards and down when you are standing up (or lift you up when you're doing a crunch).
Most of us spend more than enough time bending forwards into flexion already.
We are looking down at our phones, rounding forwards while driving the car or while holding and feeding a baby.
You don't need to get stronger doing forward flexion. You need to work on connecting to and strengthening your deep core and pelvic floor muscles.
Your deep core muscles function like a corset, creating stability in your hips and lower back.
If your Rectus Abdominal muscles get too strong, your Transverse Abdominals (part of your deep core) can become underactive, leading to hip and lower back pain.
What are Crunches good for?
Apart from strengthening your 6 pack muscles, crunches are great for showing how you tend to load your core and they are awesome for seeing an imbalance in your ab muscles. This is why they are often used as part of how we test for diastasis recti.
Using only your rectus (6 pack) muscles to do a crunch will cause your abs to bulge up.
If you bear down on your core and pelvic floor (because this is the easiest way for your body to create core strength) then your abs will also bulge up. (because this is the easiest way for your body to create core strength) then your abs will also bulge up.
This can cause leaking when you sneeze or jump and stop your diastasis from healing.
In this picture my lower belly is bulging up as I put pressure downward onto my pelvic floor and only use my rectus muscles to crunch up.
When your deep core muscles are engaged and working together with your rectus, rather than letting it take over, the crunch looks like this.
You can see that my stomach is firmer and flatter and there is no bulging.
My pelvic floor is also a lot happier as it doesn’t have to work against the pressure from improper loading.
Given that you want to strengthen ALL your core muscles to heal your diastasis, there are lots of other core exercises that are a better choice than crunches or sit-ups.
(The exception being if you have to pass a sit-up test for some reason like in the Police or Military or you just love doing crunches).
If you do want to do crunches (or sit-ups) it's vital to use the correct technique and proper core activation.
(Here's a quick test to see if you can spot the correct technique- go back to the first image in this blog post- can you see if the lady on the pink mat is bulging or using her deep core muscles?
I can see she's pushing up on her lower abs.)
To sum up: Crunches aren't a “bad” or dangerous exercise once you've healed your diastasis, but you need to progressively work up to them rather than doing them too soon with a weakened core.
Want more on healing your diastasis? Get my FREE guide full of tips to help you heal your diastasis when you're not working out.