Think the burpee can’t get any worse?

Then wait until you see the 25 variations shown by Men’s Health Fitness Director B.J. Gaddour in the video above. With names like the punching burpee, the punisher burpee, and the dead-stop burpee, they’ll make the standard version look like child’s play.

But they’re not only incredibly intense—they’re incredibly effective, too. Gaddour designed each one to challenge and improve your agility, strength, and coordination.

So give them a shot today. You could pick one, and try to get as many reps as possible in one minute. Or you could do 10 variations back-to-back as fast as you can. It’s completely up to you, so experiment.

No matter what, these variations are guaranteed to make everything burn—your muscles, lungs, and a ton of calories.