It isn't that simple Rugs. What gets players hurt in full pad practice is missing the off-season workouts which should be designed to get players ready to hit. Junior High, High school, and college all do extensive off season workouts leading up to full pad workouts to prevent this by getting joints, tendons, and ligaments in shape for the stress and torque of full practices and games.

Being "in shape" is not being in "football conditioned" as those have two fairly different requirements. The less they do before pads the more injuries you will see especially in the front 7 on either side of the ball.