The following is an excerpt from Complete Conditioning for Baseball, a book written by Steve Tamborra, a strength and conditioning coach at Georgia Tech, who has trained more than 60 All-Americans, 16 first round picks (including Mark Teixeira) and 100 players who have been drafted in baseball and other sports. The book was published by Human Kinetics Publishers.
Training for Appearance
The most common mistakes are training for appearance—beach muscles—rather than baseball performance. Overly developed chest muscles and biceps are not particularly useful in baseball. Pitchers have to be careful about getting too tight in the chest, and over-sized biceps could cause elbow tightness or changes in the pitching motion. The way to avoid these problems is to perform upper body lifts with a full range of motion.
Some lifts should be avoided. All baseball players are throwing athletes. Shoulder presses and behind-the-head lat pull-downs can place excessive stress on the shoulders. Preacher curls and bicep curls on machines can limit range of motion and add to the risk of a hyper-extended elbow.
"Bench presses," says Tamborra, "are popular among lifters but do not help develop rotator cuff muscles. The reason for the name "rotator cuff" is that the humerus (the long bone in the upper arm) rotates. Bench presses are performed in a single plane that does not involve the muscles needed for rotation. No rotation, no development of rotator cuff muscles."
Poor technique is a common mistake among baseball players. Once the player gets sloppy—using momentum instead of force—or recruiting the wrong muscle to lift a weight, the lift loses its effectiveness and the person risks injury.
Fear of Tightness
Proper weight training will not cause tightness. The baseball player who performs lifts correctly in terms of intensity, volume, speed, and range of motion is more likely to be flexible than those who over-train the wrong muscles or who under-train. Players who do not perform in the weight room are more likely to sustain injuries and more likely to experience a decrease in on-field performance as the season progresses.
Regardless of the player's position, begin a weight training program with basic lifts such as the bench press, leg extension, leg curl, and leg press. Later, progress to more advance lifts, including squats, hang cleans, glute hamstring raises and plyometric push-ups.
There are multiple lifts for each muscle or muscle group. The exercises most effective for an individual player will depend on that person's experience in the weight room, available equipment, the stage to which the player has progressed during his off-season program, and the availability of a spotter.