What does the research suggest about the benefits of strength training for baseball players?

THE MAKING OF A BETTER BASEBALL PLAYER:
Let's take the example of training a pitcher. The idea is to build basic shoulder strength before subjecting the shoulder joint and muscles to the high forces involved in whipping the arm forward at higher-than-usual speeds.

This question was looked at by the scientists from the University of Hawaii. Their research involved 45 high school and 180 university baseball pitchers, who completed three workouts per week over a 10-week period. The specifics of the research were as follows: a control group utilized only a standard-weight (five-ounce) baseball, a second group trained with both a standard and heavy (six-ounce) baseball for five weeks, followed by five weeks with only a standard and light (four- ounce) ball. The final group worked out with standard, heavy, and light balls simultaneously throughout the 10-week period.

During a typical workout, the pitchers threw just 66 pitches. For the control group, each pitch was made with a standard ball. The group which simultaneously used standard, heavy, and light balls would throw (in order) 11 times with the regular ball, 22 times with the heavy, 22 times with the light, and then 11 times with the standard baseball during a single workout. The heavy-first-and-then-light group sandwiched 11 standard throws around 44 heavy throws during the five-week 'heavy' period and 11 standard throws around 44 light ones during the final, five- week 'light' period.

After 10 weeks, the control group failed to improve pitching velocity, but the other two groups raised throwing speeds. This suggests that concurrent usage of high-resistance and low- resistance work is great for power development.