I have seen that drill done, but never really tried it.
My cardio is...
LOTS of bagwork
Jumping rope with weights on
Hopping (jumping from a full squat repeatedly)
and jogging.
(and of course sparring)
"In choosing your dwelling, know how to keep to the ground.
In cultivating your mind, know how to dive in the hidden depths.
In dealing with others, know how to be gentle and kind.
In speaking, know how to keep your words.
In governing, know how to maintain order.
In transacting business, know how to be efficient.
In making a move, know how to choose the right moment.
If you do not strive with others, you will be free from blame."
-Lao Tzu, Tao Teh Ching
An eye for an eye leaves the world blind.