Your rib cage attaches to your thoracic spine. Your diaphragm attaches to your ribs. Your pelvic floor works in sync with your diaphragm. So when your mid back can’t rotate or expand well, pressure has nowhere to go.

This is the chain that gets missed in most postpartum core conversations. We talk about the pelvic floor in isolation. We talk about the abdominal wall in isolation. But none of these structures work alone, and none of them can compensate indefinitely for a rib cage that isn’t moving.

What Actually Happens to the Rib Cage Postpartum

Through pregnancy, the rib cage flares to accommodate a growing baby, and breathing mechanics shift to manage that changing space. The lower ribs widen, the diaphragm’s resting position changes, and the whole pressure system reorganises around a body that’s adapting month by month.

That adaptation doesn’t automatically reverse after birth. Months of altered breathing mechanics and a rigid, flared rib cage leave little room for the diaphragm to move, and when the diaphragm can’t move, pressure has nowhere to go. The ribs can sit stuck in that flared, expanded position, unable to fully close down on an exhale, which means the diaphragm can’t fully ascend, which means the pressure system underneath it never gets to reset properly either.

This is why a full 360 breath matters so much more than people realise. It’s not just a breathing exercise. It’s the mechanism that lets your entire pressure system, diaphragm, deep abdominals and pelvic floor, work together the way they’re meant to.

Why This Is a Pressure Regulation Problem, Not a Gap or Lack of Core Exercises

So much postpartum core messaging focuses on two things: closing a gap (diastasis recti),or more isolated core work. Neither addresses what’s actually going on here.

This comes down to pressure regulation, and pressure regulation is the real foundation ofpostpartum core recovery. Rib mobility affects:

• How well the diaphragm can move through its full range on inhale and exhale
• Whether intra-abdominal pressure can distribute evenly, rather than poolingdownward onto the pelvic floor or outward into the abdominal wall
• How well the deep core system, diaphragm, transverse abdominis and pelvic floor,can coordinate as a unit rather than working against each other
• Your capacity to rotate, reach and load through the trunk without losing thatcoordination

If the rib cage can’t move, none of this works properly, no matter how tight your brace is or how small your gap measures.

Building Rib Mobility Back In: The Exercises

The order here matters. You need to restore range before you load rotation and reachthrough it.

Start with the deep squat rib smash – supported. This position lengthens the back body and opens the posterior rib cage, giving you a starting point to actually feel where you’re restricted before you try to move through it. Smashing the front side of the body, really emphasizes that inhale going backwards vs forwards (where most people often breath postpartum)

Add thoracic rotation – band resist. The resistance gives you feedback through the rotation, helping you control the movement rather than just moving through available range passively. At the top of the rep (on the open) that band can help pull you into a deeper stretch.

Layer in thread the needle – overhead reach. This combines rotation with overhead reaching component add a deeper stretch to the lats and upper body, which starts to bridge mobility work into something closer to how your rib cage needs to move in daily life.

Sitting back onto your heels while reaching forward helps lock you in place, whilst the foam roller allows for greater range of motion on the rotation. A true feel-good movement.

Once that range is there, it’s time to load it.

Move into the 90/90 thoracic rotation with arm bar. This works rotation through the thoracic spine while keeping the pelvis stable, isolating the mobility you’re after rather than letting the lumbar spine or hips take over the movement. The arm bar rotation requires both control and shoulder stability throughout. The straight arm helps keep this as true thoracic rotation— a hard one to cheat with.

Short lever side plank with weighted rotation asks the obliques and deep core system to control rotation from a stable base, which is exactly the kind of controlled loading that rib mobility work should be building towards.

Landmine cross press loads rotation through the trunk while you’re pressing, demanding that your rib cage and core system coordinate under load. The half-kneeling position takes the legs out of the equation as a source of stability, so the trunk has to do the work of resisting rotation while the arm presses across the body. That cross-body press line means the ribs and obliques on the working side have to control the trunk against a force that’s actively trying to pull it into rotation and extension.

½ Kneeling cable chop finishes the progressions a core variation, asking you to control a rotational force through a stable base, integrating everything the earlier exercises built. The chop pattern pulls the cable diagonally across the body, top to bottom, which asks the obliques and rib cage to decelerate and control that diagonal line rather than just resist a straight-on force. Being half-kneeling again removes the legs as a stabilising crutch, so the trunk has to own the control entirely. By this point in the progression you’ve built the range, then loaded rotation from a stable base, then loaded a cross-body press, so this pattern integrates everything the earlier exercises built into one controlled, multi-directional movement.

The Bigger Picture

You don’t live in postpartum recovery forever, you progress through it. Rib mobility work isn’t a phase you do once and move past, it’s a foundation that has to be built, then loaded, then progressed, the same as every other part of your recovery.

This is exactly the kind of work woven through every program in the app, whichever stage of postpartum recovery you’re working through. If you want a structured path that builds this in from the ground up, rather than guessing at what to do next, you can start a 7-day free trial and find the program that fits where you are right now.

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