Bat Velocity is the speed in MPH the bat head is moving toward contact with the ball. We measure Bat Velocity using Blast Technology where we test the hitter on 5-10 swings in the batting tee.
Bat velocity is an indication of potential power although, as we know, power includes a lot of other factors in addition to how fast the bat is moving. However, low bat velocity is a very strong indicator of a lack of power.
A long swing, on a batting tee can actually improve the bat velocity a little bit so you have to be careful that a hitter that has high bat velocity but a long swing will struggle with consistent contact in games.