Equipment-free exercises shouldn't be saved for vacations, at-home workouts or hotel rooms. They can be just as effective as heavy weights for building strength, says Todd Durkin, C.S.C.S., author of The IMPACT! Body Plan.

The reason: Your muscles can't tell the difference between iron and your body weight. If the exercises are challenging, you'll ignite muscle growth.

For this weekend's fitness test, Durkin chose three super-tough weight-free moves -- groiners, tombstones (a Durkin original), and rotational squat jumps -- to test your body's ability sans iron. Along with strength, you'll need power, mobility, and balance to quickly complete it with perfect form. Basically, you'll need to be fit from head to toe. (Beat your workout plateaus with this 5-move Total-Body Muscle Assault.)

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Think you have what it takes? Watch the video above to see how to perform the challenge. Durkin completed 3 rounds in 3 minutes and 37 seconds. Give it a shot and let us know how you do in the comments below.

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