Fun Topic.
I'm 5 foot 9.
I used to be able to dunk before I ripped ligaments in my ankle. =0( sad day. anyways its about two years removed from then.
I can grab the rim on a good day now.
However, vertical is actually measured from taking one step and jumping, we do it with our players every year.
A lot of them can get way above the rim when they get a running start, but its a much different story when you do it as if it were a jump ball.
Anyone interested in increasing their vertical, check out the AIR ALERT programs
Old programs, but I still think they are the most effective.
Most people who use it add at least 4 inches to their vertical. The most I've seen, one of my players added 10. which was insane. On average they gain about 4 though.
Goodluck!