That's the beauty of this workout from trainer Mathew Forzaglia, NFPT-CPT . Forzaglia knows you don't have hours to spend in the gym, but his lightspeed, single-kettlebell workout will crush your whole body and incinerate calories in just over 10 minutes.

If you're sick of standard routines with reps and sets, this workout is perfect for you, focusing only on time as you pile up reps and torch your muscles. And since it only requires one kettlebell, you can do it almost anywhere, from your local gym to your backyard. The workout will hit your abs harder than you think, too, but not in conventional ways. You won't do a situp or a crunch at any point, but you'll still get a solid core burn thanks to a lot of anti-rotation work. It's a stealth ab workout.

All you need is a kettlebell. Don't have one? This one from Onnit is a good starting point.

You'll do a quick 2-minute bodyweight warmup, then work through a two-round circuit with Forzaglia. Once you've survived all that, you'll end things with a four-minute AMRAP finisher that'll leave you breathless as you try to outrep Forzaglia. You're rarely resting during this workout, so by the time you're done, every muscle's on fire, and you're drenched in sweat. And you do that all in less than 15 minutes.

It's as time-friendly as a total body workout can get. Ready to get started? Get to work.

Round 1

20 seconds

20 seconds

20 seconds

Round 2

20 seconds

20 seconds

20 seconds

Recover for 1 minute

Circuit 1

Do each move for 30 seconds

Round 1

Round 2

4-Minute AMRAP Finisher

Do 10 reps of each move, working through the circuit as quickly as you can. Rest as needed. Repeat the circuit as many times as possible in 4 minutes.