are 15 minutes long with medium difficulty. are 20 minutes with advanced difficulty.
The idea behind these workout is, that you print them out and put them next to your skipping area. For the time you can download this generic timer with one minute training intervalls and 30 seconds rest.
I admit, these workouts are rather special and you need to set your mind to it. But they are very effective workouts no one else has done before (and after). If you need assistance with it, contact me.