Now most lady players have never learnt to “Throw” a ball at something, think baseball pitcher, or a Quarterback throwing a ball to an outside receiver.
The action is the same a “throwing “motion!
To learn the serve we used to “Throw” rackets over the court fence into a target area!
But introduce a speed gun and all changes!
The player is now focused on the Speed of the serve and is trying to “throw” everything at the ball to increase the pace!
Yes the serve gets a little faster but what the observer notices is the serve is now going into the service box with “venom”
80% of the balls were going in on the first serve !
So the moral of this is, measure what you should measure and introduce the measure that will produce the required outcome!
Hope this helps!