If you’re trying to build a stronger core, two exercises tend to appear again and again: the plank and the crunch.

On the surface, they seem to be chasing the same goal. Both train your abs, both require no equipment and both can be done almost anywhere. But they challenge your core in very different ways.

So, if you’re deciding between plank vs crunches for your abs, which one actually deserves more space in your training?

Crunches primarily train the rectus abdominis – the muscle most associated with the visible six-pack – by repeatedly flexing your spine.

That makes them a useful exercise if your goal is to directly challenge your abs through a shortening and lengthening movement.

They’re also easy to scale. You can perform them with just your bodyweight, slow the tempo to make them harder or add external resistance once standard reps become too easy.

What crunches won’t do, however, is selectively burn fat from your stomach. No amount of ab training can spot-reduce body fat from your waist. If visible abs are the goal, your overall body-fat level will matter far more than the number of crunches you complete.

Crunches can also become uncomfortable for some people, particularly if they repeatedly pull on their neck or struggle to control spinal flexion. Good technique matters, and if the movement causes pain rather than muscular fatigue, there are plenty of alternatives.

Planks train your core in a very different way.

Rather than repeatedly flexing your spine, the aim is to resist movement and hold your torso rigid. Your rectus abdominis and obliques are still working, but so are deeper core muscles alongside your shoulders, glutes and other muscles responsible for maintaining position.

That makes the plank particularly useful for developing the kind of bracing strength you need when lifting weights, running, changing direction or simply resisting unwanted movement through your torso.

The exercise is also easy to progress beyond the basic forearm plank. You can introduce shoulder taps, long-lever variations or reach one arm forwards to increase the stability challenge without necessarily adding external weight.

Try the Hand-Reach Plank

• Begin in a strong plank position with your feet slightly wider than normal for stability.
• Keeping your hips as still as possible, reach one arm straight out in front of you.
• Pause briefly, return your hand to the floor and repeat on the opposite side.
• The challenge comes from resisting the urge to rotate or shift your hips as you remove one point of contact with the floor.

Neither exercise automatically wins.

Crunches are better suited to directly training spinal flexion and loading the rectus abdominis through movement. Planks are better at teaching your core to brace and resist movement.

Strength and conditioning coach Sam Pepys favours planks when the goal extends beyond simply feeling your abs burn, because they demand more from the muscles responsible for stabilising your torso.

But that doesn’t mean crunches are useless. If you can perform them comfortably and with good technique, they remain a perfectly valid way to directly train your abs.

The smarter approach is to consider what your programme is currently missing.

If most of your core work involves crunches, adding planks, carries and anti-rotation exercises can help you develop strength in different movement patterns. If all you ever do is brace and hold positions, some controlled spinal-flexion work can provide a different stimulus.

If you had to choose only one exercise for general core strength, the plank probably offers more carryover because it trains your ability to keep your torso stable while other muscles work around it.

But you don’t actually have to choose.

A well-rounded core programme can include both dynamic exercises such as crunches and stability-focused movements such as planks.

Train your abs to move. Train them to resist movement. You’ll get more from doing both than declaring one exercise the winner.