Walk into any gym and you'll see people doing crunches, leg raises, and sit-ups — working hard on their "core." And they're not wrong to train it. But there's a good chance they're training the wrong thing for what they actually want: to lift more, move better, and stay injury-free for years.
A visible six-pack and a strong, stable core are not the same thing. They involve different muscles, different movement patterns, and different training approaches. One is primarily about how you look. The other is about how well your body holds together when you're lifting 100kg off the floor or running your fifth kilometre in a HYROX race.
You can have both. But you need to train for both — intentionally.
"Your core's most important job is not to create movement. It's to resist it — so that your hips and shoulders can do their work without your spine paying the price."
THE CORE: WHAT WE'RE ACTUALLY TALKING ABOUT
The "core" is not just your abs. It's everything between your hips and your shoulders — the muscles that surround and protect your spine from all sides. That includes your rectus abdominis (the six-pack muscle), your obliques on the sides, your transverse abdominis deep underneath, your erector spinae along the back, and your glutes and hip flexors connecting it all to your legs.
When you do a crunch, you're mainly working the rectus abdominis through flexion — the movement of bending forward. That's useful for aesthetics and for certain athletic movements. But when you're deadlifting, squatting, carrying heavy bags, or running, the most important thing your core is doing is not moving — it's staying still. It's bracing, resisting, and holding your spine in a safe position while force moves around it.
That's core stability. And it requires a completely different training stimulus.
- Resisting unwanted movement
- Protecting your spine under load
- Transferring force between upper and lower body
- Carrying over directly to lifting and sport
- Works deep stabiliser muscles
- Feels subtle — fatigue builds slowly
- Creating movement (flexion, rotation)
- Building visible muscle definition
- Higher rep, rhythmic work
- Targets superficial ab muscles
- Useful for some athletic movements
- Aesthetic results driven by body fat %
THE 4 WAYS YOUR CORE RESISTS MOVEMENT
To train core stability properly, it helps to understand what your spine actually needs protection from. There are four directions of unwanted movement — and a smart programme trains all four.
When you hold a plank, your lower back wants to sag toward the floor. The muscles bracing against that — your deep abs, your transverse abdominis — are working in anti-extension. In the real world, this is what keeps your spine safe during overhead pressing, deadlifts, and running.
If this is weak: your lower back arches under load, which compresses the lumbar spine and leads to the kind of back pain most gym-goers eventually experience. It also leaks force — energy intended to move the bar goes into moving your spine instead.
Best exercises: Plank, deadbug, hollow body hold, ab wheel rollout.
Every time you press or pull with one arm — a single-arm row, a one-arm cable press, even carrying a bag in one hand — your torso wants to rotate toward the load. Anti-rotation training builds the muscles that resist this twist and keep your hips and shoulders square.
If this is weak: unilateral loading causes compensation patterns, asymmetric wear on your spine, and eventually overuse injuries on one side. Runners often develop this imbalance without realising it — one hip drops slightly on every stride.
Best exercises: Pallof press (cable or resistance band), bird dog, single-arm carries, half-kneeling cable chop.
When you carry something heavy in one hand — a farmers carry, a heavy shopping bag, even a child on one hip — gravity tries to pull your torso sideways toward the load. Anti-lateral flexion is what holds you upright. This is largely an oblique-dominant quality.
If this is weak: you'll hitch your hip or lean your torso during heavy carries, which over time stresses the spine laterally. In HYROX, this shows up at the farmers carry station where athletes start visibly tilting by the 100m mark.
Best exercises: Suitcase carry (one kettlebell, one side), side plank, single-arm overhead carry.
Less trained but critically important — especially for deadlifts, Romanian deadlifts, and any hip hinge movement. As the load gets heavier, the spine wants to round forward. Anti-flexion is the ability of the posterior chain (erectors, glutes, lats) to resist that rounding and hold a neutral spine.
If this is weak: your deadlift form breaks down as weight increases. The rounded-back deadlift you see in gyms is usually an anti-flexion problem, not a technique problem. The technique breaks because the stability isn't there to support it.
Best exercises: Bird dog, back extensions, good mornings, Romanian deadlifts with controlled tempo.
THE STABILITY EXERCISES — HOW TO DO THEM RIGHT
These are the movements I use most with clients at Het Gymlokaal West and Bodytime in Amsterdam West. They look simple. Done correctly, with full tension and no compensation, they're harder than most people expect.
Lie on your back, arms toward the ceiling, knees bent at 90°. Slowly extend opposite arm and leg toward the floor without letting your lower back lift. Return and repeat.
On all fours, extend opposite arm and leg simultaneously. Hold for 2–3 seconds at full extension, return slowly. The goal is zero hip rotation and a level spine throughout.
Forearms on the floor, body in a straight line from heels to shoulders. Squeeze everything: glutes, quads, abs. Most people can hold a plank for a minute but are barely working their core.
Stand side-on to a cable or resistance band. Hold it at chest height, brace your core, then press straight out and hold for 2 seconds before returning. The resistance pulls you toward it — you resist.
Lie on your back, arms overhead, legs extended. Press your lower back into the floor and lift your shoulders and legs slightly off the ground. Hold the position.
On your forearm and the side of your foot, body in a straight line. The hip especially wants to sag — don't let it. Stack your feet or drop to your knee to scale the difficulty.
The obliques sit on the sides of your torso and are involved in almost every core quality — they resist rotation, assist lateral stability, and connect the upper and lower body during rotational movements like throwing, swinging, and running.
Here's the thing: heavy compound lifts already work your obliques hard. Every squat, deadlift, and overhead press asks your obliques to stabilise against rotation and lateral force. If you're lifting consistently, they're getting stimulus.
Where most people fall short is in direct anti-rotation work — the Pallof press and suitcase carry are the two movements I add most often when I see oblique weakness in a client. A side plank is also underrated for isolating lateral stability.
For aesthetics, side crunches and woodchops will add oblique mass and definition. But for function, it's the resistance-based work that builds the obliques worth having.
THE SIX-PACK EXERCISES — AND WHERE THEY FIT
None of this means crunches are bad or that aesthetic training is wrong. Six-pack training has its place — it adds volume to the superficial ab muscles, it can be a useful warm-up or finisher, and for some athletic movements (sit-up in wrestling, V-sit in gymnastics) the flexion strength genuinely matters.
The issue is when it's the only core training someone does — because then they're leaving real functional strength on the table.
Classic spinal flexion. Targets rectus abdominis. Useful for volume and definition. Keep range of motion controlled — going further doesn't mean working harder.
Hanging or lying, these target the lower portion of the abs. High hip flexor demand too. Great for ab definition — less carryover to lifting stability.
Rotation combined with flexion — hits both rectus abdominis and obliques. Good aesthetics work. Keep the movement slow and controlled rather than rushing the reps.
Demanding full ab contraction. Requires decent hip flexor strength too. Use as a finisher once the stability work is done — not as the foundation of your core training.
One more thing worth saying: a visible six-pack is mostly a body fat question, not a training question. You can have extremely well-developed abs that are invisible at 20% body fat. The six-pack exercises develop the muscle. Nutrition uncovers it. Both matter — but they're separate jobs.
HOW TO PUT IT TOGETHER
My recommendation for most people is to treat stability training as the foundation and six-pack work as the finisher. Lead with the technical movements when your nervous system is fresh, add the volume work at the end of a session when form is less critical.
Do this 2–3 times per week, either as a standalone session or bolted onto the end of a strength day. Within 6–8 weeks you'll feel a real difference in how your main lifts feel — more connected, more controlled, less back fatigue after heavy sets.
Want a Programme That Actually Builds This In?
Core stability isn't an add-on — it should be woven into every session. If you want a strength programme built around your body and goals, let's talk.
Book a Free Call →THE SHORT VERSION
Train your core to resist movement, not just to create it. Four qualities matter: anti-extension, anti-rotation, anti-lateral flexion, and anti-flexion. The deadbug, bird dog, Pallof press, hollow body hold, and side plank cover all of them.
Six-pack training is fine — crunches and leg raises have their place, and the obliques benefit from direct work too. But if you lift weights seriously, core stability is where the real performance gains live. Build that foundation first. The aesthetics will follow.