Conditioning Workout

4 rounds, each round for time,
Rest 3 mins between each round, of:
30/24 Row Calories
30/24 Ski Erg Calories
30/24 Assault Bike Calories
20/15 Row Calories
20/15 Ski Erg Calories
20/15 Assault Bike Calories
10/8 Row Calories
10/8 Ski Erg Calories
10/8 Assault Bike Calories