Studying the movement and physiology of Danielle Lawrie, Sport Science compares a 70 mph fastball to a 90 mph baseball pitch
. On average, a baseball is released approximately 55 feet from home plate, resulting in a reaction time of .44 seconds for the hitter. By comparison, a 70 mph softball, released from an average distance of 37 feet from the plate, will result in 0.35 seconds of reaction time for the batter.
In other words, a softball batter has 20% less time to react to a pitch than a baseball batter.