Not at all....Lacrosse is a great cross-fit sport for football providing good footwork, speed and agility workouts which carry them into the Fall. This is why a lot of football players back east are required to play lacrosse by their football coaches. D-Ends can get good side movements and steps through Lacrosse (google and watch the feet of some of the defenders on the lacrosse field). It is also a heads up sport; meaning they learn to keep their eyes up and open therefor the focus moves away from the body forcing the athlete to trust his body.
Call the office if you have any specific questions. Hope this helped.