Here are two abstracts from scientific studies done on the use of weighted balls. Coop DeRenne, who authored both of these articles, is a strength and conditioning consultant for the Chicago White Sox Major League baseball team. A reminder: scientific journals go through a very strict peer review process in which a committee of academics scrutinize every part of the paper and protocol to ensure that it is truthful and scientifically significant.
Effects of Under- and Overweighted Implement Training on Pitching Velocity
By Coop DeRenne, Ronald K. Hetzler and Kwok W. Ho
This study examined the effects of training with various combinations of standard, light, and heavy baseballs on pitching velocity. High school (n = 45) and university pitchers (n = 180) were pretested for pitching velocity and randomly assigned to two experimental groups and one control group. Group 1 pitched with a heavy, light, and standard baseball 3 days a wk for 10 wks. Group 2 pitched with a heavy and standard baseball for the first 5 wks and then a light and standard baseball for the final 5 wks. Group 3 served as a control and pitched with a standard 5-oz baseball for 10 wks. Pitching velocities were determined by electromagnetic radiation radar. The velocity of 15 consecutive pitches was calculated to represent mean pitching velocity for each subject.
RESULTS Groups 1 and 2 improved significantly in throwing velocity, but no improvement was observed for the control group.
CONCLUSIONS The results suggest that training with weighted implements using either protocol can improve pitching velocity.
SOURCE The Journal of Strength and Conditioning Research: Vol. 8, No. 4, pp. 247–250. Effects of Under- and Overweighted Implement Training on Pitching Velocity. Coop DeRenne, Ronald K. Hetzler and Kwok W. Ho
Here’s the second one.
Effects of Weighted Implement Training on Throwing Velocity
By Coop DeRenne, Alan Blitzblau and Kwok W. Ho
Thirty high school varsity male baseball pitchers were assigned randomly into an Over-weighted Implement Training Group (OITG), an Under-weighted Implement Training Group (UITG) or a Control Group (CON). During the 10-week training, OITG threw balls that systematically varied from 5 to 6 ounces and UITG threw balls that varied from 4 to 5 ounces. Throwing velocity of a standard ball was determined before and following training using electromagnetic radiation radar. Validation of the radar gun was performed prior to the experiment using a three-dimensional computerized motion analysis system.
All three treatment groups showed various degrees of improvement in throwing velocity after 10 weeks of training. However, OITG and UITG showed significantly greater improvement than the CON when gain scores were compared (p < 0.05).
The results of this study suggested that a much broader spectrum of weight training methods may exist.
The Journal of Strength and Conditioning Research: Vol. 4, No. 1, pp. 16–19. Effects of Weighted Implement Training on Throwing Velocity Coop DeRenne, Alan Blitzblau and Kwok W. Ho