Sprinting and backpedaling for 5 yards doesn't sound too hard -- until you add fast, muscle-burning groiners and pushups at either end.

"You'll be up and down and up again, challenging your heart, lungs, and every last muscle fiber," says Todd Durkin, C.S.C.S., author of The IMPACT! Body Plan. "Everything is working. There is no rest." Are you up for the challenge?

Here's how to do it: Sprint 5 yards, and then perform 10 groiners. Without resting, backpedal to the starting point and perform 10 pushups. That's 1 round. Repeat 4 more times. By the time you're finished, you'll have completed a total of 50 yards, 50 groiners, and 50 pushups. (Think you have the pushup down? Think again. Here are 5 Body-Weight Exercises You're Doing Wrong.)

Your goal: 2 minutes and 29 seconds.

Watch the video above to see how to perform the challenge. Then let us know your time in the comments below. Did you beat Durkin?

Try these 5 Secrets to the Perfect Workout and you'll never be held back in the gym again!

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