If your calves are stuck at skinny-kid status, then you're probably making one or more of 3 mistakes

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

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