Tire flips look tough and demand every ounce of strength you can muster. They're definitely not for everybody

Tire flips look tough and demand every ounce of strength you can muster. They're definitely not for everybody

Tire flips look tough and demand every ounce of strength you can muster. They're definitely not for everybody

Tire flips look tough and demand every ounce of strength you can muster. They're definitely not for everybody

You're on your third and last set of squats. You take slow breaths, feeling the adrenaline surging through your veins.

Tire flips look tough and demand every ounce of strength you can muster. They're definitely not for everybody

Tire flips look tough and demand every ounce of strength you can muster. They're definitely not for everybody

Whether you're a diehard cruncher or stalwart planker, your ab workout could probably use a tune-up.

Get fitter, faster. Burn calories quickly with this high-intensity circuit! If you've got 15 minutes, you can send fat fleeing.