Whether you are a pitcher, catcher, infielder or outfielder, proper arm motion when you throw the baseball is important to your success. Not using a full extension of your arm is known as "short-arming" the ball and it causes a loss in distance and velocity. Short-arming sometimes resembles a shot putt motion and results from not bringing the arm back through the full range of motion when you throw. You can fix short-arming with a couple of drills.
Knee Throwing Drill
Move about 10 to 20 feet away from a partner. Kneel on the ground so the knee of your throwing arm is on the ground and the other foot is flat on the ground out in front of you.
Hold the ball with a normal grip, and move your arm straight back so your palm is facing down and your hand is on top of the ball. Your fingers face away from your body.
Move your arm in a circular motion so your hand comes through by your ear, with your fingers pointing up.
Point your front shoulder at your target and keep your elbow higher than your shoulder when you release the ball. Extend your arm out toward your target after the ball is released.
Long Throwing Drill
Find a partner and start playing catch from a normal distance to warm up your arms. Stay in the same spot for 10 to 20 throws.
Step away from one another two steps after each throw once your arms are warmed up. Emphasize a full extension and range of motion with each throw.
Continue to step back after each throw until it is a challenge to make the distance. Make a few throws from that distance, and then gradually move your way back to the start in the same fashion.