Neither sit-ups or crunches are the easiest moves for beginners to tackle, but get them both right and you’ve pretty much got fitness in a headlock.

But do you know the difference and the benefits of each one?

• With both, you need to lie down on your back with your knees bent. For a crunch you will only need to bend forward enough so that your shoulders lift off the ground. With a sit-up, you need to lift your entire back off the ground
• Livestrong.com says the crunch can help tone and develop the muscles at the front and sides of your torso, specifically the rectus abdominis and obliques. When performed regularly, this core-strengthening exercise can help improve your balance, posture, athletic performance and make daily tasks easier
• Likewise Livestrong.com says the sit-up also works the muscles of the abdomen but doing them correctly will also increase hip strength

The easiest way to understand the differences between them is to watch the same person performing them both. Here, then, is Amy McCauley of Gold’s Gym, showing you how to do crunches curtesy of Livestrong.com. The key here is to avoid rounding out your back and bringing your chin to the collarbone, avoid pulling your elbows inwards, try to keep your chin slightly lifted and to engage the centre of your stomach. Remember to exhale as you lift up and inhale as you lower. Simples.

How to Do Crunches by Livestrong.com

And now here’s Amy with a textbook example of how to do sit-ups. Top tips here are to avoid jerking upwards and to try and lead with your stomach to create a c-curve as you lift up. To make it even tougher you can straighten your legs to give an even harder stretch or if you’re finding it difficult to reach the sitting position you can grab onto your thighs on the way up.

How to Do a Sit Up by Livestrong.com

Basically, the sit-up is the bigger, meaner brother of the crunch, and it’ll totally steal your dinner money then push you into the changing rooms.