Abs! We all want them, but there are only so many crunches one can do before we have to face facts that our abdominals need a little something extra to kick into sixth gear (sixth gear for six-pack abs – it’s a metaphor that I don’t think we will be continuing with).

When researching how to get great-looking abs, it can sometimes feel like a fool’s errand, as if you need to already have visible ab muscles in order to get them. But I’ve discovered one particular workout that you can use to help carve out a more defined stomach. Following this really simple move should help you out immensely. I started seeing results pretty quickly, so hopefully it works out the same for you. All you need is a bench, a BOSU ball, a floor, and a full range of motion. It’s called the Alternating BOSU Ball and Floor Crunch  — get ready to learn your new favourite ab workout.

You can always tell who knows what they’re doing on a weight floor of the gym by who is using their full range of motion. Muscles grow because the body is repairing slight tears, building over time the size that we all want. Whether you’re working your biceps, your triceps, your pecs, or, in our case, your abs, if you’re not utilizing your full range of motion then you’re not going to see the results your time and effort deserves. When it comes to your abs, it can be tricky. It can be hard to find equipment that allows for it, but really all you need is a bench and a BOSU ball. If your gym is quiet, then try and steal a bench that’s bolted down. This will stop it shifting underneath you as you do the exercise, but there’s nothing wrong with a regular old bench. You can perhaps try and weigh it down with a kettlebell or dumbbell if you find it moving around too much.

You’re going to alternate from side to side of the bench for this move. On one side of the bench, place a BOSU ball. Sit on the bench with your butt ever so slightly hanging off the back and then slide down so you’re positioned on the BOSU ball, your legs still draped over the bench. Now you’re just going to do a standard crunch. Simple? Well, thanks to the BOSU ball your back – and as a result of that, your abdominals, too – will be arching much further than you’re used to. The effect should be instantaneous if your ab muscles aren’t used to such a wide range of motion. Do 20 to 30 sit-ups in this position, making sure you you keep a neutral spine and your eyes fixed to the ceiling.

Once you have completed your first set, then immediately get back up and move to the other side of the bench. This time slide your butt off the edge — carefully, you don’t want to hurt your coccyx! — so that your legs are draped over the bench with your butt tucked under the bench, your legs perpendicular to the floor and your back flat on the ground. Try for 20 to 30 regular crunches in this position. You may ask why you’re doing it this way when I just said the range of motion thing is the key to success. Well, that’s true, but not only should you still be trying for a slight arch in the back, even when on the floor, but by throwing in these more standard floor crunches you are essentially shocking your muscles into growing. They won’t know what you’re doing and they will be forced to react. Also, doing crunches in this position works a different side of your muscles as when using the BOSU ball. So by moving from one side to the other and using a different form each side, you are hitting your abs at multiple angles, neither of which they have experienced before.

When you have done a set of those, try not to waste time and instead get right back over to the other side. Place your butt on the BOSU ball again, arch yourself backwards over it and leave your legs draped over the bench and do another 20 to 30 of the crunches. Your stomach will be feeling sore, but power through it because it means you’re hitting muscles you have never hit before. That is a good thing, remember. That is what will make them grow. Once you’ve finished that set, move over to the other side of the bench again, your back flat against the ground. And then again to the BOSU ball side, and lastly one more time flat on your back for a total of three sets of each exercise.

You’ll be shocked at how well-worked your abs are and how effective it is to switch up your usual routine of sit-ups, crunch machines, and hanging leg raises. To see video of it, check out Scott Herman’s YouTube page right here. You can thank me later.