This 20-minute circuit is all about working hard and recovering quickly. Grab a medium dumbbell (something you can lunge, bicep curl, press overhead and row). In between each dumbbell strength set you have 90 seconds of cardio. Every time you get around to strength again, your rep count of each exercise increases by 2. And most of all, have fun!
Increasing reps by two each round:
Single sided reverse lunge
Single arm bicep curl
Single arm overhead strict or push press
Single arm bent over row
Begin with 4 reps and increase by 2 each round, adding in 90 seconds of cardio between each round!