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This is the most important thing to do when working your abs, according to a personal trainer

a photo of a man doing sit-ups
(Image credit: Shutterstock)

If you’ve ever done an ab workout, you’ll probably have heard your trainer telling you to “engage your core”, but what does this mean, and how do you actually do it? Engaging your core might sound like something you can ignore, but it’s important when it comes to supporting your spine and pelvis during ab workouts. 

A lot of trainers will tell you to “think about sucking your belly button into your spine” to engage your core, but it’s actually a little more complicated than just sucking your stomach in. Engaging your core tightens your mid-section — your four abdominal muscles, your hip flexors and glutes, and your lats and erector spinae to keep your spine stable. Read on to find out exactly how to engage your core, and the signs you’re not doing it properly. 

Looking for more workout inspiration? Here’s the best ab exercises to work your core, what happened when our fitness editor did 100 dead bugs a day for a week, and how long you need to hold a plank to see results

How do you engage your core? 

To find out more, we spoke to Luke Zocchi, Head Trainer at Centr (opens in new tab) and Chris Hemsworth's personal trainer. Zocchi said, “To engage your core you want to lengthen your spine to make your back straight, breathe in deeply into your rib cage and draw in your belly button."

“The best way to engage this final step is to think what your reaction would be if someone was going to hit you in the stomach. I know it sounds aggressive but that natural reaction of how you would tense your stomach is how you engage your core muscle. As you get better at this you can engage your core and continue to breathe at the same time which is the best practice.”

Here Zocchi touches on the difference between sucking in your stomach and tensing — if someone was going to punch you in the stomach, you wouldn’t suck your belly in. It might help to think about zipping up your abs.

Why do you need to engage your core? 

As we’ve already mentioned, engaging your core is important when it comes to preventing injury to your spine when working on your abdominal muscles. In fact, studies (opens in new tab)have found that working on engaging your core during everyday activities like walking the dog, or sitting at your desk, can help with chronic back pain. 

When it comes to optimizing your performance, the jury is still out, and there’s still a lack of research between core stability and performance. That said, runners often cite a strong core as a reason they are able to run stronger and faster. 

What are the signs you’re not engaging your core? 

If you’re not engaging your core during your workouts, you’re likely to know about it, as your form will suffer. Without a strong core, your back is likely to arch during shoulder presses and push-ups, and you’re likely to have a bad posture when sitting at your desk. You’re also likely to find it difficult to press your lower back into the ground in exercises like leg lifts. 

If you struggle to engage your core and are suffering from lower back pain, it’s a good idea to chat with a personal trainer or doctor. 

Jane McGuire
Fitness editor

Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past five years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.