The best way to strengthen a throwing arm is to do long toss drills. For softball start by warming up and stretching. Then make 10 throws from around 70' move to 90' make around 10 throws move to 110' make 10 throws then 130' make 10 throws. Make sure you keep moving back 20' until you have reached your maximum distance. Do this drill three to four times a week and your arm-throwing strength will increase.

Jackie,

You need to build a good solid base of strength in your core area, your back, and especially your shoulders. And I'm not talking about getting into the weight room and pumping a bunch of iron. Simple body weight exercises that will help.

I've got a couple of DVD's on my website... www.bioforcebaseball.com that can help. You can also find a local trainer that specializes in conditioning for baseball and softball players. That's the best place to start. As Coach Rob McAfee says above, long toss is a good way to build arm endurance and some arm speed.

Good Luck,

Coach Bill Mooney

After they make their 100 throws a day in warm-ups at practice, have them throw every day from the outfield into home plate. Also squeezing a rubber ball can help. Fill a tennis ball with pennies and throw it at warm-up distance.

When you have established the proper mechanics, no matter how much strength you gain your accuracy won't get affected. Proper strengthening workouts will help increase your throw. Strengthening your legs, core, back, arms and shoulders will increase on your throwing power.

http://www.softballperformance.com/blog/softball-conditioning-core-training-is-the-secret-to-more-power/

long toss helps alot.. start off fairly close to you partner and then as you warm up throw farther and farther away until you can barely reach her. you don't have to throw hard either.. but after a while, doing this excercise over and over, your arm will get stronger and stronger.

You have to throw all the time, a hole lot.