"I strongly believe that throwing into a screen, and not to a partner, has led to faster arm speeds. "
The best example of this would be in the area of developing arm strength. There are no areas where we have 200 linear feet to throw our long toss, so we have been forced to adapt and develop throwing programs that work in our space and are sufficiently challenging enough for our players to grow. Besides giving our pitchers a much needed break from competitive innings on the mound, one of the huge advantages that has come from our space constraint is our consistent throwing into a screen through the off-season. I strongly believe that throwing into a screen, and not to a partner, has led to faster arm speeds. We still ask players to throw to a spot on the screen in order to repeat their arm action, but because we are not trying to throw to a specific target it allows players to think about 2 things:
1. Maximizing Arm Speed - no fear of missing a target means players can "let it fly"
2. Making Mechanical Adjustments - throws into a screen allow players to detach themselves from the results and focus more on the how the ball feels coming out of their hand.
There is no denying that to pitch or to play effective defence you need players to be able to throw to a target, but during the off-season our priority is developing healthy, strong arms. As we move closer to the season we begin to refocus the players newly developed arm strength towards a specific target, but until that point they have an opportunity to throw their long toss without inhibition. When we are outside I see players dial back their arm speed just so they don't over-throw their partner, but this is never an issue indoors.
Finally, as coaches we have the ability to focus players on improving the strength and efficiency of their throwing footwork in various on-field situations. One part of our throwing program includes a "position-specific" segment where players can choose the game situation they want to throw from. I encourage players to work on throws they don't normally have the chance to practice. For example:
Infielders
1. Off a bobbled ball where you pick it up barehanded
2. Flat on the ground after diving for a ball
Outfielders
1. Off a fly ball (OF's typically work throwing off ground balls far more than fly balls)
2. After an outside turn where the ball is fielded on the run on the glove side
Catchers
1. After blocking a ball
2. Back picks to 1st & 3rd
In the end, we are focused on making sure our players don't get stuck in the "victim mentality" ... and coaches shouldn't either. Get creative and don't attribute limited progress to uncontrollable factors like the weather.
How do you modify your throwing programs to develop arm strength indoors? What tools do you use?