These are four very effective throwing exercises I do as an Olympic javelin thrower that help strengthen and condition my shoulder and torso/core for throwing. I would have to believe these same exercise would work well for baseball pitchers and baseball throwing too?
In #1 I use weighted balls that weigh between 400g to 1.5 kg. I’ll do 300 to 500 per session twice a week. The focus is on range of motion,staying relaxed and rhythm.
Drill #1: Alternating Weighted Ball Throws- Right / Left Arm.
In #2 I use a 1kg medicine a ball. Although this a stationary exercise it is far from static. You will notice that as I lean back on the exercise ball, as I catch the medicine ball rebounding off the wall, it compresses and then pushes me forward as I throw. I am acting and reacting with each throw decelerating and accelerating the ball. When you time it right you can get a tremendous ab, lat, tricep and chest stretch with each throw. I often think of this drill as the speed bag exercise that boxers do. I’ll do between 1000 to 3000 of these throws per session twice a week.
Drill #2: Seated Two Handed Medicine Ball Throws
In #3 I use a weighted ball: 400g, 600g, 800g, 1kg and 1.5kg. It is the same concept as the #2 Drill but I do half the amount per session - 500 to 1500 - and do them is sets of 25 reps.
Drill #3: Seated One Arm Weighted Ball Throw:
In #4 I use a 1 kg med ball again. I’ll do this exercise before I throw javelin. The focus is on correct sequencing and throwing for height as well as distance. I’ll do 10 to 25 reps each side and straight.
Drill #4: Two Handed Overhead Medicine Ball Throws - for height / distance.