Are Planks and Crunches Actually Bad After Having a Baby?

The "postpartum exercises to avoid" list you were handed is mostly out of date. A physiotherapist explains what the evidence actually says about planks and crunches — and how to tell if you're ready.

Somewhere between the six-week appointment and your first attempt at a workout, someone handed you a list. No planks. No crunches. No sit-ups. Nothing on your stomach. Definitely no twisting.

You may not remember where the list came from — a reel, a friend, a well-meaning trainer, a pregnancy app that never updated its postpartum section. But it stuck. And now every time you think about doing something for your core, there's a small voice asking whether you're about to make things worse.

Here's the honest version, and it's more freeing than the list: the blanket "never do this" advice is largely out of date. The research has moved. What matters far more than which exercise you pick is whether your body is ready for it and how it responds when you do it.

Let's go through it properly.

Why were you told to avoid planks and crunches in the first place?

The logic went like this: pregnancy stretches the linea alba — the connective tissue running down the middle of your abdominals — and creates a gap between the two sides of the rectus abdominis. That's diastasis recti, and it happens to essentially everyone by the end of pregnancy. Crunches shorten the rectus abdominis. Planks load the whole front of the abdomen. So, the reasoning went, both must pull that gap wider.

It's an intuitive theory. It's just not one that held up well when people actually studied it.

The problem with the blanket ban is that it treats every postpartum body — six weeks out, six years out, symptomatic, asymptomatic — as the same body, and every version of an exercise as the same exercise. A wall plank and a forearm plank are not the same demand. A slow, controlled curl-up with a good exhale and a fast, breath-held sit-up are not the same movement.

What does the research actually say about crunches and diastasis recti?

More recent work suggests curl-up-type exercises don't automatically widen the gap, and can be part of effectively strengthening the abdominal wall when they're performed well and introduced at the right time. Some studies have found the linea alba actually tensions and narrows during a curl-up rather than splaying open.

The nuance that gets lost: "not automatically harmful" is not the same as "the right place to start." A curl-up on day one of a rebuild, before your deep core and pelvic floor are coordinating with your breath, is a bit like adding weight to a lift you haven't learned the pattern for yet. Not dangerous. Just not the most useful thing you could be doing with that ten minutes.

Not sure whether you have a gap at all? Here's how to check for diastasis recti at home, step by step.

Are planks safe with diastasis recti?

Same answer, same nuance. A study of an abdominal stabilisation programme in women 3–36 months postpartum — one that included a traditional forearm plank with abdominal bracing — found it reduced diastasis. So planks are not inherently the villain.

But a full forearm plank on the floor is one of the most demanding anti-extension positions there is. It asks your entire canister — diaphragm, deep abdominals, pelvic floor — to manage load while you're horizontal and holding position. If that system isn't talking to itself yet, the plank doesn't build it. It just reveals that it isn't there.

The fix isn't avoidance. It's a ramp:

1. Wall plank (hands on a wall, body at a steep angle)
2. Incline plank on a counter or high table
3. Incline plank on a couch or low bench
4. Knee plank on the floor
5. Straight-arm plank
6. Forearm plank

You move up a step when the current one is genuinely easy and symptom-free — not when a calendar says so.

How do you know if you're ready for planks and crunches?

Rather than a date, use signals. Broadly, most people are ready to start layering in more demanding core work when:

• Breath and core are connected. You can exhale and feel your deep abdominals and pelvic floor gently engage, without gripping your ribs or holding your breath. (If that connection isn't there yet, start with diaphragmatic breathing.)
• You can manage pressure in easier positions first. Dead bugs, heel slides, bird dogs, side planks from the knees — comfortable and controlled.
• You're not symptomatic during daily load. No leaking, no heaviness, no doming, no pain when you lift the car seat or carry a toddler up the stairs.
• You can hold the position while still breathing. If you have to brace and hold your breath to stay in it, it's above your current capacity.

If any of those are missing, that's information — not failure. It means there's a step below this one that will make this one work.

What should you watch for while you're actually doing them?

This is the part that matters more than the exercise name. Stop, regress, or modify if you see or feel:

• Doming or coning — a visible ridge or tent along the midline of your belly
• Bulging downward at the pelvic floor, or any sense of heaviness or pressure
• Any leaking
• Pain — at the scar, in the low back, in the pelvis
• Breath-holding you can't get rid of

None of these mean damage is being done. They mean the load is above what your system can currently distribute — and that's a cue to step back one rung, not to quit.

Is there anything genuinely worth postponing?

Some things are simply poor value early on, because they demand a lot and teach very little:

• Full sit-ups and V-ups in the first weeks of a rebuild
• Loaded rotation and Russian twists before rotation feels comfortable unloaded
• Double-leg lowers with your feet held off the floor
• Any breath-held maximal bracing
• Jumping and running before you've built the capacity for it — different topic, same principle

Postponing isn't the same as banning. These come back. They come back when your system can distribute the load, which is a matter of weeks to months of the right work, not a permanent restriction.

What's the better order of operations?

If you take one thing from this article, take the sequence rather than the list:

1. Breath. Diaphragmatic breathing, ribs moving, pelvic floor moving with it.
2. Connection. Gentle deep-core engagement on the exhale, in easy positions.
3. Anti-movement. Dead bugs, bird dogs, side planks from the knees, incline planks.
4. Load. Carries, squats, deadlift patterns, real-life lifting.
5. Everything you actually want back. Planks on the floor, crunches, running, the class you miss.

Most people who feel stuck aren't doing the wrong exercises. They're doing step four's exercises with step one's foundation — and then blaming themselves when it doesn't feel good.

The bottom line

Planks and crunches are not on a permanent banned list. They're advanced positions on a ramp, and the useful question was never "is this exercise bad?" — it was "is my body ready for this today, and how does it respond when I try it?"

Being cleared isn't the same as being recovered. But being cautious isn't the same as being careful, either. Careful looks like a progression. Cautious often just looks like waiting.

Written by Harleen Kalra, Registered Physiotherapist (BC, Canada).

This article is general education from a physiotherapist's perspective. It is not individualized physiotherapy advice, does not create a therapist-patient relationship, and is not a substitute for care from a licensed healthcare provider in your area. Harleen Kalra is a physiotherapist registered in British Columbia, Canada. For personalized assessment and treatment, please see a licensed pelvic-health provider where you live.