Core Myths · Week 1
Your Core
Isn't What
You Think It Is.
And crunches aren't training it. The "abs = core" myth has been costing women real strength for decades. Here's what's actually true.
Ask most women what their core is and they'll point to their stomach. Ask them how they train it and they'll describe crunches, sit-ups, or planks held for time. The fitness industry spent forty years selling women on this version of core training — and in doing so, left them significantly undertrained in the muscles that actually keep them upright, pain-free, and strong for life.
This is the first post in a series on core myths because the gap between what women have been told about the core and what the anatomy actually shows us is one of the most consequential misconceptions in women's fitness. It affects how you move, how you lift, how you age, and how resilient your body is to injury and dysfunction over time.
Let's start at the beginning.
The anatomyWhat Your Core Actually Is
Your core is not your abs. Your abs are part of your core but they are one layer of a complex, three-dimensional system of muscles that wraps around your entire trunk, from your pelvis to your ribcage, front to back, inside to outside. Thinking of the core as your stomach is like thinking of a house as just its front door. Technically part of it. Not the structure.
The core system includes four primary muscle groups working in concert and only one of them is what most women have been training:
The deepest abdominal muscle. Wraps around the trunk like a corset. Its primary job is spinal stabilization and intra-abdominal pressure, not movement. A crunch doesn't reach it. Bracing does.
The base of the core canister. Works in coordination with the transverse abdominis and diaphragm to manage pressure and stabilize the pelvis during load. Almost never trained deliberately and chronically undertrained in women.
Your primary breathing muscle — and a core stabilizer. Proper breathing mechanics directly affect spinal stability. How you breathe during a lift is core training. Most women breathe backwards under load.
The deep spinal extensors running along the back of the spine. Critical for spinal stability, posture, and load transfer. Chronically weak in women who sit for long periods and rarely targeted by traditional "core" exercises.
The muscles you can see. The ones crunches target. They matter but they are the outermost layer of a deep system, and training them in isolation while ignoring everything else is like painting a wall while the foundation crumbles. The rectus abdominis flexes the spine. The obliques rotate and laterally flex it. Neither provides the stabilization the deeper layers are responsible for.
"The core is a canister — top, bottom, front, back, and sides — that generates and transfers force, stabilizes the spine, and protects the pelvis under load. Training it means training the whole system. Not just the part you can see."
The mythWhy Crunches Don't Train Your Core
Crunches train spinal flexion. That's it. They shorten the distance between your sternum and your pelvis repeatedly, under the weight of your upper body. For the rectus abdominis (the most superficial abdominal muscle), the one that makes up the "six pack" — crunches are an adequate isolation exercise. For the core as a system? They are almost entirely irrelevant.
Here's why. The core's primary job is not to flex. It is to resist movement. To provide a stable platform from which your limbs can generate and absorb force. When you squat, deadlift, carry a load, or hold an overhead position, your core is working isometrically bracing against the forces trying to destabilize your spine. That is the function. And that function is not trained by repeatedly folding yourself in half on a mat.
Crunches: Rectus abdominis in spinal flexion. Trains the most superficial layer of the core in the least functional pattern available. Often compresses lumbar discs under load.
Sit-ups: Hip flexors more than abs. Creates significant lumbar compression. Considered contraindicated for most populations by current exercise science standards.
Planks held for time: Better, but static endurance in one position doesn't translate to dynamic stability under load. A two-minute plank does not prepare your spine for a deadlift.
Bicycle crunches: Adds rotation to spinal flexion. Marginally more useful. Still training the outermost layer in a pattern that doesn't reflect how the core functions during real movement.
The functionWhat a Trained Core Actually Does for You
This is the part that connects core training to everything you care about long-term because a truly trained core is not about aesthetics. It is about function. And the functional benefits compound dramatically with age.
- Spinal protection under load. Every time you pick something up — a grandchild, a bag of groceries, a five-gallon bucket — your core is what stands between that load and your lumbar spine. A weak core transfers force to passive structures: discs, ligaments, joints. A strong core absorbs and distributes it correctly.
- Injury prevention. The majority of low back pain has a core stability component. Not because the back muscles are weak in isolation — but because the deep stabilizing system isn't doing its job and the back muscles are compensating. Training the core correctly addresses the root cause, not the symptom.
- Force transfer in lifting. In a squat, deadlift, or press, the core is the bridge between your lower and upper body. Power generated in your legs has to travel through your trunk to reach the bar. A stable, braced core transfers that force efficiently. A soft core leaks it, meaning you lift less, fatigue faster, and risk more.
- Posture and uprightness over time. The postural changes associated with aging — the forward head, the rounded shoulders, the compressed lumbar spine — are significantly driven by weakness in the deep stabilizers of the trunk and posterior chain. Training the core correctly maintains the structural uprightness that keeps you moving well for decades.
- Pelvic floor health. The pelvic floor does not operate in isolation. It is part of the core canister and responds to pressure changes driven by breathing, bracing, and load. Women who train their core correctly, with attention to breath and intra-abdominal pressure, support pelvic floor function in ways that isolated Kegel exercises simply cannot replicate.
The trainingWhat Actually Trains the Core
If crunches aren't the answer, what is? The short version: compound lifts, anti-movement patterns, loaded carries, and deliberate bracing practice. Here's what that means in practice:
Deadlifts and squats: The most effective core exercises available. Both require the entire core canister to brace and stabilize against significant load. Nothing else trains the deep stabilizers under load the way these two movements do.
Loaded carries: Farmer carries, suitcase carries, overhead carries. Walking with load forces the core to maintain stability through dynamic movement — exactly what it needs to do in real life. Wildly underused in women's programming.
Anti-rotation and anti-lateral flexion: Pallof press, single-arm work, suitcase deadlifts. Training the core to resist rotation and side-bending builds the obliques and deep stabilizers in their actual function, resisting movement rather than producing it.
Dead bugs and bird dogs: The rare "ab exercise" that earns its place because both train the deep stabilizers in a controlled, spine-neutral position without spinal flexion. Excellent for learning to brace correctly before adding load.
Breathing and bracing mechanics: Learning to create intra-abdominal pressure before a lift, the 360-degree brace that pressurizes the entire core canister, is foundational. It is a skill, and it is trainable. Most women have never been taught it.
Notice what's on that list. The exercises that train the core most effectively are not core exercises in the traditional sense. They are compound strength movements that demand full-system stability. This is exactly why women who lift heavy, consistently and correctly, have stronger cores than women who do daily ab circuits, even if the ab-circuit women "feel the burn" more.
The myth is over.
Your core is not your abs. Crunches are not training it. And the decades of advice pointing women toward mat work, hollow holds, and endless sit-ups has left an entire generation undertrained in the muscles most responsible for their longevity, their pain-free movement, and their ability to stay strong and independent as they age.
The good news is that the training that actually builds a functional core is the same training that builds everything else you need. Compound lifts, progressive loading, intelligent programming. You don't need a separate core day. You need to squat, hinge, carry, and brace. Consistently. With weight that challenges you.
That's it. That's the core training program that will serve you for life. No crunch required.
Next week: your nervous system — what it is, why it runs your training, and why understanding it changes everything about how you recover, perform, and progress.
