- The core is more than your abs: it includes the obliques, deep trunk muscles, back and glutes.
- Its main job is resisting movement and transferring force.
- Dead bugs, planks, side planks, Pallof presses and carries cover the essentials.
- Visible abs depend mostly on body fat, not the number of crunches.
What your core actually is
When people say core, they often mean the six-pack muscle at the front. In reality the core is a whole cylinder of muscle around your trunk: the rectus abdominis at the front, the obliques at the sides, the deep transversus abdominis wrapping around, the spinal muscles at the back, the diaphragm on top and the pelvic floor underneath, with the glutes and hip muscles closely involved.
These muscles work together to stiffen the trunk. That stiffness protects the spine under load and lets force travel from your legs to your arms, which is what happens in every push, throw, carry, sprint and wall ball. Thinking of the core as a team rather than one muscle changes how you train it. Because the diaphragm is part of that team, breathing well and bracing well are closely linked.
Resisting movement is the main job
Most of the time, your core's job is not to bend the spine but to stop it bending when something is trying to bend it. Coaches group core exercises by what they resist:
- Anti-extension: stopping the lower back arching. Examples: plank, dead bug, ab wheel rollout, body saw.
- Anti-rotation: stopping the trunk twisting. Examples: Pallof press, single arm rows, bird dog.
- Anti-lateral flexion: stopping you bending sideways. Examples: side plank, suitcase carry, single arm overhead carry.
- Hip flexion with a stable spine: hanging knee raises and leg raises, which also train the lower abs and hip flexors.
A well-rounded plan includes something from each group. That is very different from 200 crunches a night, and far more useful for lifting, running and everyday life.
What about crunches and sit-ups?
Crunches are not dangerous for most people, and they do train the rectus abdominis. The spine is designed to bend. The issue is that they cover only one function, and they are often done in huge numbers with no added load, which does not build much strength.
If you enjoy them, a few sets of 10 to 20 weighted cable crunches or decline sit-ups is a perfectly reasonable addition. Just do not make them the whole of your core training.
The same goes for the endless ab circuits on social media. They leave you with a burn but rarely with much more strength, because the challenge never really increases.
Hanging knee raises are a better choice than most floor ab exercises once you have the grip for them. They train the abs and hip flexors while you hold your whole body steady, and they are easy to progress towards straight leg raises.
Do the big lifts train your core?
Yes, a lot. Heavy squats, deadlifts, overhead presses and carries require serious trunk stiffness, and studies measuring muscle activity show the core working hard during them. Many strong lifters do very little direct core work.
But the big lifts mainly train bracing against bending forwards and backwards. They do less for rotation, side bending and the kind of control needed for sport, running or HYROX, where the trunk has to stay steady while the arms and legs move. A little direct core work fills those gaps, and it helps beginners learn the bracing that makes the big lifts safer. Our guide to breathing and bracing explains the technique.
A simple core routine
Two or three times a week, at the end of a session, pick two or three exercises from different groups:
- Dead bug: 3 x 8 slow reps each side, lower back gently pressed into the floor.
- Side plank: 3 x 20 to 40 seconds each side.
- Pallof press: 3 x 10 each side with a pause at arm's length.
- Suitcase carry: 3 x 20 to 30 metres each side.
Progress by adding time, load or difficulty: move from a plank to an ab wheel rollout, from a knee side plank to a full one, from a light suitcase carry to a heavy one. Quality beats quantity. A 30 second plank held perfectly beats a sagging three-minute one. If you only have five minutes, one hard carry at the end of a session covers a surprising amount.
For HYROX and hybrid athletes, loaded carries and anti-rotation work give the best return, because the race asks you to hold your posture while carrying, lunging and pulling under heavy fatigue.
Core, back pain and pelvic health
A strong trunk is useful for people with back pain, but there is no single core stability fix. For most non-specific back pain, general exercise and gradually loading movement helps more than a special abs routine. If back pain is severe or spreading down the leg, see a GP or physio promptly. If it comes with numbness around the genitals or buttocks, new bladder or bowel problems, or weakness in both legs, call 999 or go to A&E.
The pelvic floor is part of the core, and for some people, particularly during pregnancy, after childbirth and around menopause, it needs specific attention. Leaking during jumps, skipping or heavy lifts is common, but it is not something you have to put up with. Lycan Strength's on-site physiotherapy covers men's and women's health, with 20% off for members.
Visible abs are mostly about body fat
No amount of core work burns fat from your stomach specifically. Visible abs depend mostly on body fat levels and genetics. Core training builds the muscle underneath; overall calorie balance decides whether you can see it. Our guide on how to lose belly fat explains why spot reduction does not work.
What core training will do is make you more solid under load and more comfortable in daily life, from carrying a toddler to lifting a suitcase into the boot. That is a better reason to do it anyway.
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Questions
How often should I train my core?
Two or three short blocks a week at the end of sessions is plenty for most people, alongside compound lifts that already train the trunk.
Are planks better than crunches?
They train different things. Planks train the core to resist movement; crunches train it to bend the spine. Resisting movement carries over better to lifting and sport, but both have a place.
Will core exercises give me a flat stomach?
They strengthen the muscles underneath, but a flatter stomach depends mostly on overall body fat, which comes down to calorie balance.
Is core training good for back pain?
General strengthening, including the trunk, often helps. There is no single best core exercise for back pain, and severe or unusual symptoms should be checked by a professional.
General guidance for healthy adults. If you have a medical condition, injury or are pregnant, check with a health professional before changing your training or diet.
