Every pitcher from youth to the major leagues wants to increase the velocity of their pitches. While being able to pitch fast can be from physical gifts, there are quite a few things you can do to add several MPH’s to your fast ball.
First, mechanics are a huge part of pitching. Be sure to work with your coach to have the right mechanics from the start including having your non-throwing foot 1-2 inches in front and making sure to land perpendicular to home until right before landing. Always be sure to release the pitch when the front foot plants allowing your legs to help increase the speed of your pitch.
Outside of mechanics, there’s plenty of training points including weight lifting that will help increase the speed of your fastball. Throwing fast is about more than just the strength of your arm. Be sure to increase leg strength through weight lifting and also do core work through crunches and sit ups. Upper body weight lifting should focus on the shoulders and forearms.
Various training methods can help increase speed also. Try pitching long distances starting at 1/3 longer than the distance you would throw in a game and working up to double the pitching distance. Throw in some long toss to help build up the shoulder and back throwing motions. Depending on your age, 200-300 feet should be more than enough length.
Watch this video from eHow to learn a few more tips on increasing your pitching speed.