Understanding Rapsodo Hitting Data: Launch Angle

Launch angle (LA) is a hot topic in baseball as of late. Ever since Statcast introduced launch angle along with many other metrics in 2015, there has been a discussion about its relevance. Some have called launch angle a “type of swing”, but let’s call it exactly what it is: a metric to describe a batted ball.  

It is the vertical angle measured in degrees of the ball as it leaves the bat. Every batted ball has a launch angle: a grounder straight into the ground has a negative LA, a pop up has a positive LA – along with every other ball in between. 

One important point to note is that launch angle is not measured from the ground, but from a plane parallel to the ground going directly through the ball at impact.  

Rapsodo 

In the Rapsodo hitting app, launch angle in degrees is shown along with a visual representation of the data. The representation shows the initial path of the ball as it leaves the bat. The horizontal line represents what a zero-degree launch angle looks like in reference to other balls:

The other line is the path of the ball as it leaves the bat, creating the angle. 

What does your launch angle mean? 

Launch angle can be used to determine the hit profile of a ball in play. MLB.com defines a ground ball as anything with less than 10 degrees of launch angle, a line drive at 10-25, a fly ball at 25-50, and anything higher than that a pop fly. 

While these are reliable ranges, it is important to note that a hit ball’s exit velocity can shift a range. For example, a ball hit softly at 10 degrees will likely look more like a ground ball, while a hard hit ball at 25 degrees could be a line drive home run.  

How can I use launch angle data to improve my players? 

Launch angle data can be used to identify if a player is hitting the ball too high or low to be a successful player. If they are hitting too many ground balls and pop ups, it is unlikely success will follow during the game. Look at how different hit profiles performed in the MLB in 2018: 

As shown, line drives and fly balls are clearly the most beneficial outcome to a batted ball, as they slug and hit for the highest average of any batted ball type. 

This is not to say that everyone should be trying to hit the ball extremely high in the air because some players do not possess the power necessary for this type of swing. Players, at a minimum, should be aiming for the line drive (10-25 degree) range with every swing to maximize chances of success.