For years, my default response to coning was simple: see it, fix it. Any bulge or ridge down the midline during a movement meant the pressure wasn’t being managed properly, full stop. And that’s because that was exactly what I was taught throughout all my pre/postnatal education. These days I hold that view a lot more loosely, particularly when the movement itself still looks controlled.

That change didn’t happen overnight. It came from years of coaching women through pregnancy and postpartum, watching what actually happens in real bodies and then going back and checking that against what the research says. Here’s what coning actually is, why the old blanket rule doesn’t hold up, and why avoiding it entirely might be doing more harm than the coning itself.

What coning actually is

Coning is the ridge or bulge that shows up along the centre of your abdomen during certain movements, most often ones that load the rectus abdominis: a curl up/crunch, a sit up, or even just coming up off the floor. Mechanically, it happens when intra-abdominal pressure meets the linea alba, the band of connective tissue running down your midline, and that tissue yields slightly rather than staying taut.

That’s the what. The “so what” is far less black and white.

It can signal a real problem. It can also be completely normal.

There’s a version of coning that does matter. When it shows up alongside breath-holding, bearing down, or a trunk and pelvic floor that have lost their coordination, that’s a pattern worth correcting. But in that case, the coning isn’t really the problem on its own. It’s a visible marker that something upstream has broken down.

There’s also a physical detail that sharpens that judgment: hard versus soft coning. A soft cone gives when you press into it. There’s still slack in the tissue, and it tends to show up with passive positions, like lying on your side or leaning forward at the hips, rather than active loading. A hard cone is rigid to the touch, which tells you more pressure is hitting that tissue in that moment. This distinction hasn’t been tested in a randomised trial the way the curl-up findings below have. It comes from prenatal fitness specialists and pelvic health physiotherapists reasoning through tissue mechanics in their own work, not from controlled research. But it’s useful in the same way the rest of this picture is: as information, not as its own trigger. Hard coning showing up alongside breath-holding or lost coordination tells you more than soft coning would in that same moment, it adds detail to a pattern that’s already worth addressing. On its own, without those other signs, it’s still just a body under load, not a new reason to stop.

Compare that also to what’s happening physiologically as pregnancy advances. The linea alba stretches and softens, and the rectus muscles spread to accommodate a growing baby. That’s the tissue doing its job, not failing at it (and this language matters). Seeing a cone appear during abdominal flexion later in pregnancy is what you’d expect from a body adapting correctly, not evidence that something’s gone wrong.

The same holds true after birth. A client working her diastasis down from a wider gap to a narrower one can absolutely still show some coning along the way, and that visual doesn’t cancel out the strength and closure she’s actively building.

What the evidence actually shows

This is one of the cleanest examples of a rule that sounded protective but was never actually tested.

Nearly every pregnant woman develops this separation, and most of it resolves on its own. A study that tracked 84 first-time mothers with ultrasound found that 100% of them met criteria for diastasis recti by 35 weeks. By six months postpartum, that number had dropped to 39%. So the widening itself isn’t a marker of anything going wrong; it’s close to universal, and the body largely walks it back afterward.

The exercise most likely to cause visible coning doesn’t make the gap worse. A randomised controlled trial put postpartum women with diagnosed diastasis through 12 weeks of curl ups and head lifts, exactly the movement pattern people are told to avoid. The group doing the exercise showed no worsening of their inter-recti distance compared with women who avoided ab work entirely. What they did gain was measurable improvement in abdominal strength and thickness, with no downside in pelvic floor symptoms, back pain, or pelvic girdle pain.

When the researcher who led that trial was asked directly why curl-ups had been off-limits for so long, she pointed to fear of intra-abdominal pressure and the visible bulge some women get, not to any prior evidence that it caused damage.

It’s not an isolated finding either. Reviews of the wider diastasis and exercise literature keep landing on the same conclusion: the evidence base is thin and inconsistent, and it’s never actually supported the strict restrictions that became standard advice.

What the avoidance actually costs

This is the part I think gets missed. We’ve built a huge amount of certainty around a rule that was never backed by data.

When coning is treated as an automatic reason to stop, women get steered away from core work at the exact point in training where they need it most. That strength underpins load transfer, spinal stability, and how well the rest of the body moves and holds up. Cutting it out because of a visible ridge that may simply reflect tissue doing what it’s meant to do isn’t a cautious choice. It’s giving up something useful in exchange for protection against a risk that isn’t well supported.

Where the actual line sits

None of this means coning should be ignored outright. It means the rule needs more nuance than “if you see it, stop.”

Coning paired with a breakdown elsewhere, breath-holding, bearing down, loss of pelvic floor coordination, is genuinely worth addressing. Coning showing up on its own, in a body doing exactly what pregnancy or postpartum recovery requires of it, deserves more room and less panic.

That’s a harder line to hold than a blanket rule. It’s also the one the evidence actually supports.

None of this works if the language stays the same. Every time coning gets called dangerous instead of informative, women learn to fear their own bodies instead of understanding them. The rules need updating, but so does the way we talk about what’s actually happening underneath them.

That’s the standard I hold myself to. I’m not interested in growing a business by making someone afraid of their own body first. If something’s worth flagging, I’ll tell you why and what to actually do about it. If it’s not, I’d rather build your confidence than your fear.

References

1. Mota, P.G.F., Pascoal, A.G., Carita, A.I., & Bø, K. (2015). Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain. Manual Therapy, 20(1), 200–205. https://doi.org/10.1016/j.math.2014.09.002
2. Gluppe, S.L., Ellström Engh, M., & Bø, K. (2023). Curl-up exercises improve abdominal muscle strength without worsening inter-recti distance in women with diastasis recti abdominis postpartum: a randomised controlled trial. Journal of Physiotherapy, 69(3), 160–167. https://doi.org/10.1016/j.jphys.2023.05.017
3. Skoura, A., Billis, E., Papanikolaou, D.T., Xergia, S., Tsarbou, C., Tsekoura, M., Kortianou, E., & Maroulis, I. (2024). Diastasis recti abdominis rehabilitation in the postpartum period: a scoping review of current clinical practice. International Urogynecology Journal, 35(3), 491–520. https://doi.org/10.1007/s00192-024-05727-1
4. Benjamin, D.R., van de Water, A.T.M., & Peiris, C.L. (2014). Effects of exercise on diastasis of the rectus abdominis muscle in the antenatal and postnatal periods: a systematic review. Physiotherapy, 100(1), 1–8. https://doi.org/10.1016/j.physio.2013.08.005