Notice how even high level softball games almost never show radar readings, unlike baseball? Top women softballers top out around 70 mph which is average speed for a high school freshman baseball pitcher. I used to hear about male softballers who could hit 100... in the days before radar. LOL Most of those played exhibition softball and likely juiced the facts to draw paying crowds.
Throwing underhand just isn't as fast as doing it overhand. Baseball submarine pitchers often top out in the low 80s although a few are faster.
[edited by: jsinger at 7:18 pm (utc) on Oct. 31, 2006]