Assault Bike Ladder 

1 minute on // 1 minute off

1 minute on // 50 seconds off

1 minute on // 40 seconds off

1 minute on // 30 seconds off

1 minute on // 20 seconds off

1 minute on // 10 seconds off

...then go back up the ladder until you finish with 1 minute on // 1 minute off // 1 minute on, done!