One of my favorite exercises to do when I’m time crunched: the humane burpee. (Those are two words I bet you never thought you’d see together.)

Created by my good friend Dan Martin, a powerlifter and former firefighter, the exercise works key movement patterns, hits a ton of large muscle groups at once, and revs your metabolism . . . which all sound a lot like the benefits of the standard version of the burpee.

But here’s how the two differ: In the burpee, you go from a jump to a squat to a pushup to a squat to a jump again.

In the humane version, however, you replace the jump with a kettlebell swing and the squat with a goblet squat. You’re actually adding weight, and, therefore, increasing the intensity of the movement.

Related: THE 21-DAY METASHRED—an All-New Body-Shredding Fitness and Diet Program From Men’s Health

So why the hell does Martin call it “humane” then? Because he has you follow a decreasing rep scheme as you do it. This allows you to go as hard as possible from start to finish, while maintaining proper form and control during every single rep.

 
Other than that, it’s just plain cruel. (And so are these: The 3 Hardest One-Exercise Workouts You’ll Ever Do.)

Do it: Perform 15 kettlebell swings, followed by 5 goblet squats and 5 pushups. Then perform 15 swings, followed by 4 goblet squats and 4 pushups. Continue this pattern—doing 15 swings, and reducing the squat and pushup rep count by one every round—until you complete only a single rep of the squat and pushup.

Related: 10 Exercises That Burn More Calories Than Running

Do this as fast as possible while keeping perfect form. Rest only when needed.

Your goal: 4 minutes or less.

If you do the math, that comes out to 75 swings, 15 goblet squats, 15 pushups for a total of 105 reps—which is a ton of quality work in a ridiculously short amount of time.