Hey all. I have been playing ball for close to 20 years (baseball for 8, slow pitch for 10), I’m 29 now.
I find I just don’t have the juice I used to have on my throws. I’m still pretty accurate, but would like to add some more steam and distance to my throws.
I play short stop right now, but I do get rotatted to the outfield.
What kind of exercises can I do to strengthen my arm so I can throw harder, faster and farther?
Thanks
MtM
Speaking as a softball firstbaseman, you should not be throwing to my glove like you would in hardball. You should be trying to throw it through my chest.
In hardball, my glove would be the target. In softball, I tend to stand up straight, offering you no glove target to shoot for. You need to try and hit me dead center of my chest with as hard of a throw as you can (at least hit me somewhere). By doing it this way, I find I’m able to reach in any direction for your throw if it’s off line (I will stretch out after you get about halfway through your move to me, but will not commit to a direction --left of me, right of me, in the dirt, high-- until you release the ball).
Another thing I’ve seen outfielders from the better teams in our league do, is warm up not with a softball, but with a regulation football. They all have cannons, so it must help out to some extent.
My team needs a SS. Feel like playing in a mens league in Scranton?
Any decent martial artist knows that the power of a punch comes from your hip, not your arm. If you’re not generating power in your hips, you need to work on your technique.
Learning to give a ton of effort when you throw will help. Some people have some extra grunt in them but don’t use it. The immediate psychological and emotional build-up before a throw can mean another couple mph.
Oh yeah, don’t blow your shoulder out either. 
Couple of things you can do:
Loosen up before a game or practice. Not just your legs but your arms, shoulders, and back too. You can’t throw -hard if your body is tight, plus you’re risking an injury.
Don’t squeeze the ball. You’ve no doubt heard coaches say “Hold the ball like an egg!”. This is a good point. If you squeeze it, you get tension in the arm. Tension=tightness=poor throw
Work on getting your hips and legs into the throw. Sounds easy, but it’s really the secret.
Most of all, THROW. Play catch as often as you can (using a football, as Casey suggested is a good way to strengthen your arm and loosen it up before games).
Ever play long-toss (where you and a buddy start out 20 or so feet apart and play catch while taking a step or two back every so often)? You want to keep moving back until you can’t throw straight balls to each other (i.e. no pop-ups or rainbows). This is the best way to strengthen your arm.
Good luck!
Carefully cut open a tennis ball along a seam. Fill the ball with something heavy - sand, rocks, pennies, etc. Superglue the seam shut - voila! - you now have a heavy warmup ball. After warming up your muscles a bit as mentioned above, play short toss with the heavy tennis ball. Don’t throw hard, just toss it for about 5 minutes before you take the field. This will help build up your throwing muscles. Also, the softball will feel like a feather in your hand after tossing the heavy ball!