Today's workout starts off with back squats, arguably the best exercise to target all the major muscle groups in the lower body. I like them so much that I've even included them in your circuit workout!
The key to an effective squat is to drop down low enough that your thighs are at parallel (if not lower) to the floor at the bottom of the movement. Think about pressing through your heels and squeezing your glutes as you return to the starting position. By the second set, your glutes should feel like they're on fire!
Once you finish your squats, move right into your circuits. Try to complete your 200-meter rows and burpees as fast as possible. For the other exercises, try to move quickly through them, but don't go so fast that you compromise form. Go heavy with the weight, but not so heavy you can't complete the prescribed number of reps.
You can rest 5-10 minutes between each circuit, but keep the rest periods between rounds as short as possible.