Whats is the average speed of a college running back?

There's no single average speed for a college running back. Speed varies greatly depending on position within the backfield (some are more focused on power than speed), the specific college team, and even the individual player's athleticism.

However, you can expect a range. While some might be slower, many successful college running backs will have a 40-yard dash time in the 4.4 to 4.7 second range. That translates to an average speed during a 40-yard dash of roughly 15-18 mph. Keep in mind this is just a snapshot of speed during a short burst; game speed and sustained speed over longer distances will be lower.