Check out the documentary on Netflix titled: Fastball. There's a big difference at where the fastball is clocked now opposed to where they clocked them in times past. They used to be clocked a few feet from home plate, whereas, now they're clocked coming out of the pitchers hand. This is how Aroldis Chapman's pictch was recorded in 2010 clocking in at 105.1 mph. However, that same pitch clocked a few feet in front of home plate clocked in the upper 90's. Still lightning fast no doubt, but there's a little more to the "fastest fastballs" being registered now and their comparison to the fastest of our past.