Im 14 years old, 5'8 and i have a 30 inch standing vert. Uh, i could only touch the backboard on rare ocassions and now after 5 months of training, i can touch rim easy, and sometimes grab it.
Air Alert did improve a little bit of my vertical before i got slight knee problems, but all i can say is, do the exercises on a soft cushion-like mat, or it will kill in the long run....i can promise you that.

So just use a padded mat or a really soft surface and you will be absolutely fine...btw, im starting AA3 again!
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Height:5"8 (173cm)
Age:14 yrs old
Arm Length: 76 cm
Standing vertical: 27"
Running 1 legged vertical: 29.5"
Running 2 legged vertical: 30.5"
Goal: Dunk a basketball by mid-way next year