The Ascending frenado is a highly complicated type of strumming technique. It is not only difficult when considering the execution of the strum itself but also physically as it can take it’s toll on our fingers and knuckles alike.
Take a close look at the zoom video where you can observe the physical execution of this strum. Try it out until it starts to sound like a dry “tack” type sound. If you manage to get this sound, then you are well on your way to mastering it.
Be certain to practice this as much as you can and ensure that enough breaks are taken in between practice sessions because of the toll it takes on your fingers. Do not be afraid to get any calysis on your fingers as you will need it to reinforce the strength and your fingers endurance.