This 20-minute ab workout builds core strength without weights

Crunches are the pillar of many great ab workouts, but endless repetitions can quickly grow boring. Thankfully, you can keep things interesting while still working your core with this 10-move ab workout, with several crunch variations to build mid-body muscle without weights. 

While you could use one of the best ab rollers to give your midsection a workout, you don't need any equipment for this short session, making it an ideal option when you're at a busy gym, training at home, or looking for a quick workout while traveling. 

The routine has been designed by personal trainer Joe Wicks — known as The Body Coach — to target your abs, develop your core and strengthen your lower back. You'll perform each exercise for 40 seconds, take a 20-second rest, then start on the next move. Continue this until you've hit all exercises once, then repeat this 10-move circuit for a 20-minute workout. 

It's a good idea to learn how to do a plank before you start, but you can also follow Wicks' demonstrations to practice your technique as you go. There's no set number of repetitions to complete here either, so the key is to exercise intensely while focusing on your form to get the most from this short session. 

Watch The Body Coach's 20-minute ab workout

This workout style is known as high-intensity resistance training (HIRT), where the aim is to exercise in short bursts without many breaks. You'll find many HIRT routines that need weights, like dumbbells and kettlebells, but Wicks' session uses your body weight to work your muscles instead. 

Keeping the intensity high helps raise your heart rate, so you'll burn more energy than during a similar routine at a steady pace. In the longer-term, this helps boost your metabolism (the amount of energy you burn at rest) for all-day fat-burning results. 

Lowering your body fat is a key component of building visible six-pack muscle, but training your abs has a whole host of other benefits too. People use abs and core interchangeably, although the two terms have slightly different meanings. Your core is a section of mid-body muscle that includes your rectus abdominis — the muscle responsible for the six-pack aesthetic. 

So, training your abs also strengthens your core, which helps improve your balance, increases your stability and workout performance, and can even promote circulation. Though, if you enjoy working out with weights, You can get similar results by picking up one of the best kettlebells and learning how to do kettlebell swings.