In blocks of 3 minutes. If you complete the reps add on another 3 minute block and repeat until you are unable to finish all of the reps in the allowed time.
Round 1: 9 Thrusters and 27 Double Unders, 9 Thrusters and 27 Double Unders
Round 2: 11 Thrusters and 33 Double Unders, 11 Thrusters and 33 Double Unders
Round 3: 13 Thrusters and 39 Double Unders, 13 Thrusters and 39 Double Unders
Round 4: 15 Thrusters and 45 Double Unders, 15 Thrusters and 45 Double Unders
Continue to add 2 Thrusters and 6 Double Unders each round