I have played this game long enough to know those pitching drills that are not only a waste of time but will hurt your performance or hurt your arm. My favorite has to be extreme long toss. Great concept, throw the ball as far as you can straight up into the air, on flat ground, because this is going to help you throw harder, when you are on a hill, throwing down the mound, when you are pitching. This is like telling a golfer to take Happy Gilmore swings and hit the ball as hard as you can, because this is going to help you stand still and drive the ball straight down the fairway, with power.
Here is another one of my favorite waste of time pitching drills.
The kick your leg over a bucket drill, after you throw the ball. This makes a lot of sense! A drill that is teaching you what to do after you throw the ball. This is like telling golfers to fist pump after you hit the ball, this will make you shoot better because Tiger Woods does this. What is the point of teaching something that occurs after the delivery? When the drive leg moves up after a pitch this is called a recoil and should not be a voluntary actions.
The last waste of time drill that could hurt you physically, if not mentally, is the pull down drill.
This is coaching pitchers to pull the ball down during release. This drill usually follows the extreme long toss drill. This drill is a total waste of time because hard throwing pitchers never pull the ball down. They release the ball over their head and finish chin tucked and over their front foot. Pulling the ball down to release would train you to finish with your head pulling down with your arm. This will kill velocity and could cause serious UCL damage. This is a drill that goes completely against high velocity pitching mechanics.
Just because a coach gives you a pitching drill, doesn’t mean it is harmless.
Many pitching coaches have no idea of how to coach the skill of pitching. They do not study mechanics and they do not have an understand of the position outside of playing it. Just because you have played something doesn’t make you an expert. Just because I drive a car doesn’t make me a race car driver. Make sure you do your homework before you take advice from someone who didn’t do his.