[Husker] VB question

[Mike Nolan]

Here's a excerpt from the LJS's story on UNL's come-from-behind win over
Minnesota in volleyball yesteday:

"Despite dropping the second set, the Huskers' pride took over in the 
third as Nebraska held Minnesota to negative hitting percentages in 
the third and fourth sets."

Can someone explain to me what a negative hiting percentage is?

See http://huskerextra.com/sports/volleyball/article_d9bceaae-4e01-5df3-b1ab-7111063dd5ba.html
--
Mike Nolan