Get ready to lift heavy! For this five-exercise circuit, you’ll do 30 seconds of work, followed by 30 seconds of rest. That’s how you know that you’ll be working hard! You won’t rest in between the rounds, so take water and a breather as needed during those 30 second rest breaks. Repeat this circuit 3 or 4 times through. You’ll need a dumbbell, kettlebell and ab roller for this one.