Overweight & underweight baseballs

Training Pitchers with Overweight and Underweight Baseballs

Escamilla RF, Speer KP, Fleisig GS, Barrentine SW, Andrews JR. Effects of throwing overweight and underweight baseballs on throwing velocity and accuracy. Sports Medicine 29(4):259-272, 2000.

A review was conducted to determine how throwing overweight and underweight baseballs affects baseball throwing velocity and accuracy. Two studies were found that examined how warming up with overweight baseballs affected throwing velocity and accuracy of 5 oz regulation baseballs. One of these studies showed significant increases in throwing velocity and accuracy, while the other study found no significant differences. Three training studies (6-12 weeks in duration) using overweight baseballs were conducted to determine how they affected ball accuracy while throwing regulation baseballs. No significant differences were found in any study. From these data it is concluded that warming up or training with overweight baseballs does not improve ball accuracy.

Seven overweight and four underweight training studies (6 - 12 weeks in duration) were conducted to determine how throwing velocity of regulation baseballs was affected due to training with these overweight and underweight baseballs. The overweight baseballs ranged in weight between 5.25-17 oz, while the underweight baseballs were between 4-4.75 oz. Data from these training studies strongly support the practice of training with overweight and underweight baseballs to increase throwing velocity of regulation baseballs.

Future research is needed to determine what effect, if any, training with overweight and underweight baseballs has on risk of injury. In addition, research should be initiated to determine whether throwing kinematics and kinetics are different between throwing regulation baseballs and throwing overweight and underweight baseballs.