Finding max hr. and training zones.

I have a question about finding a persons max heartrate. Is it the
average heart rate over a set time like a min. or is it the max rate
that you can get your heart up to. I ran the Wabasha bidge last year
as fast as I could and at the top I reached 192. So I used that number
as the base for setting my zones last year. But last month I did a
sprint (Skate skiing) workout up some hills balls out and I topped out
at 196. So is that my max or was that really my max plus 110%?