Throwing velocity is a performance measurement used for assessing baseball players, particularly in pitchers. Pitchers are constantly seeking out ways to increase their pitching velocity, as higher velocity is looked at as a measurement of success. Research has been conducted to look at the effects of weight training, medicine ball training, ballistic training, proper mechanics, and throwing under- and overweighted baseballs on throwing velocity.

In a study conducted by Newton and McEvoy (1994), they looked at the effects of an 8-week conventional upper body weight training (barbell bench press and barbell pullover) and upper body medicine ball throws (two-hand chest pass and two-hand overhead throw) on throwing velocity and strength levels in twenty-four male baseball players. Of the two groups the conventional upper body weight training group showed a significant increase in velocity (4.1%) and strength levels (22.8%) The medicine ball throwing group showed no significant increase in throwing velocity, but did show a significant increase in strength (8.9%). This may suggest that an athlete needs a proper foundation of strength before gaining benefit from a plyometric program.

Similar results were found in a study by Swangard (1965) during an 8-week upper body resistance training program with college pitchers. The exercises included the arm pullover, standing press, biceps curl, shoulder shrug, supine lateral raises, wrist curl and extension, ulnar and radial deviations, and squats. Swangard also found a significant increase in throwing velocity.

McEvoy and Newton (1998) also studied the effects of ballistic training on velocity. During a 10-week preseason period, 18 pro players trained using explosive bench press throws and squat jumps for 3 sessions every two weeks with loads approximately 30-50% of the players 1 rep max. Significant increases in throwing velocities (2%) were reported during the 10-week program.

Werner et al (2008) looked at the relationship between pitching mechanics and pitch velocity. Fifty-four college baseball players participated in the study and it was found that throwing velocity was most effected by larger body mass, a shorter interval from stride foot contact to maximum shoulder external rotation, increased knee flexion at stride foot contact, increased elbow flexion at stride foot contact, the later the head moved forward relative to the hips, increased maximum shoulder external rotation, increased elbow flexion angular velocity, increased upper trunk rotation angular velocity, increased knee flexion at release, and increased forward trunk tilt at release. The 9 factors above, plus body mass, accounted for 68% of the difference in throwing velocity for the fifty-four athletes who participated in the study. The mechanical factors observed not only helped increase throwing velocity, but can also help reduce the stress placed on the throwing elbow and shoulder. A lot of movements happen before the release of the baseball from a pitchers hand. The more efficient a pitcher can be with those movements before the release of the ball, the less stress they will put on their throwing arm.

Although resistance training and ballistic training have shown to help increase velocity, one of the most functional methods to increase velocity is throwing under- and overweight baseballs.  The concept of using weighted implements as strength and conditioning aids for throwing sports has been around for decades. The former Soviet Union began using under- and overweighted implements with their track and field athletes decades ago (DeRenne & Szymanski, 2009; Escamillam, Speer,  Fleisig, Barrentine, & Andrews, 2000 ). The theory behind throwing an underweighted implement is that the arm will move at a faster speed, but with less muscle force generated (DeRenne, & Szymanski,2009). Conversely, when throwing an overweight implement, the arm will move at slower speeds, but will generate more muscle force (DeRenne, & Szymanski,2009).

Throwing weighted implements has carried over to the game of baseball as well, particularly with the training of pitchers. Past research has shown significant increases in throwing velocity when throwing under- and overweighted baseballs (DeRenne, & Szymanski, 2009; Escamilla et al., 2000).  One of the leading researchers in under- and overweighted ball throwing is Coop DeRenne.  DeRenne et al. conducted many under- and overweight throwing studies from 1982 to 1988 (Escamilla et al., 2000). DeRenne’s objectives were to 1) determine the ideal weight ranges of under- and overweight baseballs; 2) determine if training with overweight and underweight baseballs increased throwing velocity with 5oz regulation baseballs; 3) determine ideal pitch ratios and sequences for weighted baseballs; and 4) determine the incidence of arm injuries due to training with overweight and underweight baseballs (Escamilla et al., 2000).

DeRenne et al. most recently conducted a study from 1987 to 1988 that included 225 high school and college baseball pitchers who were randomly and equally divided into overweight, underweight, and control training groups (Escamilla et al., 2000). Groups 1 and 2, the underweight and overweight integrated groups respectively, threw underweight, overweight, and regulation baseball in their program, while group 3, the control group, threw regulation baseballs only. The 10-week throwing program showed significant increases in throwing velocity in the group that threw overweight + regulation baseballs (group 1) and in the underweight + regulation baseballs (group 2).  The control group that threw only regulation baseballs (group 3) did not see a significant increase in throwing velocity.  There was approximately a 4 to 6% increase in groups’ 1 and 2 throwing velocity.

Findings by Litwhiler and Hamm support the findings of DeRenne et al.  Lithwhiler and Hamm (1973) conducted a 12-week overweight baseball throwing program with 5 college pitchers . The purpose of Litwhiler and Hamm’s research was to determine the effect an overweight implement had on throwing velocity and accuracy. This study differed from DeRenne et al. (1994) in that their research was conducted over a longer period of time, they used heavier baseballs (7-12oz), and they tested accuracy. Although there were some different variables between the studies, results were very similar. Over a 12-week period from pre-test to post-test, throwing velocity increased an average of 5.0 m/s (Escamilla et al., 2000).

The purpose of this study was to determine the effect of a 6-week throwing program using under- and overweight baseballs on throwing velocity. It was hypothesized that college-aged pitchers throwing under- and overweight baseballs would see a significant increase in throwing velocity after completing 6-weeks of training.



Subjects were recruited from an NCAA Division III baseball team and the participation was strictly voluntary.  This study was approved by the University Institutional Review Board. Subjects were recruited for the study via an announcement at the first team meeting. It was made clear that participation was entirely voluntary and subjects that were interested in participating read and signed an informed consent document. The participants were randomly divided into a weighted ball training group or the control group. To participate in the study, the pitchers had to meet the following criteria: 1) must currently be pitching with no injuries; 2) must not be currently participating in any other weighted ball throwing programs; 3) must be able to complete all weighted ball throwing drills correctly and with max effort; 4) must be able to throw with max effort during the throwing velocity pretest and posttest; and 5) must be able to attend 85%-100% of the training sessions.

This study examined the effects of a 6-week underweight and overweight baseball throwing program on college pitchers throwing velocity. As college pitchers are resistance training and still gaining strength through maturation, a control group was used to compare the effects of training the experimental group (weighted ball group). To minimize the effects of a pitchers training status and age on throwing velocity, participants were randomly assigned to either the experimental group or the control group.  After a baseline test was taken during week 1 of throwing, the pitchers then went on to complete either 6 week throwing program with weighted baseballs or without. On the last day of the 6 week throwing program the pitchers were then tested again. The velocity from the weighted ball group and non-weighted ball group were assessed to determine if there was a significant difference in velocity increase between the two groups.


Description of Weighted Ball Throwing Program

The progression of the throwing program is outlined in Appendix C.  In essence, the weighted ball throwing program consisted of training 3 days a week for 6 weeks. The program will consist of 20-30 minutes of warm-up, 30-45 minutes of weighted ball training, and 20-30 minutes of rotator cuff strengthening and scapular stabilization exercises.  The warm-up consisted of a dynamic warm-up, shoulder warm-up, hip mobility, and a throwing progression to prepare the participants for throwing weighted baseballs. The control group training mirrored that of the weighted ball training group minus the actual throwing of the weighted baseballs. The Control group completed the weighted baseball throwing drills with a regulation, 5 oz baseball. All other throwing such as bullpens, long toss, and drills were consistent throughout the two groups.

Prior to the pretest and the first week of weighted ball training, all participants were familiarized with the test and the drills that would be used during the weighted ball training. During the familiarization period the pitching coach demonstrated all drills, corrected any poor technique during the weighted ball drills, and answered any questions.

The weighted ball throwing program consisted of 7 different throwing drills thrown with 5 baseballs of different weights (21oz, 14oz, 7oz, 5oz, & 4oz). All participants were instructed to make each throw for each drill at maximum effort. The first two drills were thrown with all 5 baseballs, the next two were thrown with only the 7oz, 5oz, and 4oz, and the last three drills were thrown with only the 5oz and 4oz baseball (Appendix A). The control group completed all the drills with maximum effort, but with a regulation baseball only. During all training sessions participants were instructed on proper technique and received verbal motivation to increase their effort.  The drills that were performed during the study put the pitchers in positions similar to those explained previously in the Werner et al (2008) study. Pitchers were given cues that helped them focus on getting into these positions which in turn would help them throw the ball more efficiently and give them their best chance to help increase their velocity.

The weighted ball training was implemented in a periodization format (Baechlem & Earle, 2008). As the weeks progressed so did the volume and intensity of the throws. Week 1 started with two throws per ball plus pretest were completed on the first day; during week 2 & 3 three throws per ball; during weeks 4 & 5 there were four throws per ball; and during week 6 only two throws were made per ball plus the posttest was completed on the third training day of the week.

Pretest and Posttest of Throwing Velocity

Pretest and posttest were both completed outside at the universities baseball field during the team’s fall non-traditional season. The pretest was completed on the first day of the training session before any weighted ball training, and the posttest was completed on the third day of training during week 6. In both tests, participants were asked to do the warm-up they have been instructed to do prior to the start of the program, and once they felt ready to make 5 throws at maximum effort then the test was completed. Participants tested their velocity using the “turn and burn” drill. The turn and burn drill (Figure 1) is completed by the pitcher standing 10 yards away with the back to their intended target. On the coach’s queue, the pitcher will back pedal for three to five yards as fast as he can, once reaching the three to five yard mark the pitcher will begin to rotate his shoulders and hips back toward the intended target and while beginning to throw the ball as hard as they can at the target.

Figure 1. Turn and Burn Drill

Velocity was measured using the Stalker Sport 2 radar gun made by Stalker Radar (Plano, TX). Of the five throws made by the participants the highest velocity ball thrown out of those five was taken and recorded.

 Statistical Analysis

Change in mean throwing mean velocity from pre-test to post-test between groups was analyzed using a paired t-test.  All statistical analysis was completed using SPSS (Version 19, IBM, Armonk, NY).


Eighteen of the nineteen subjects completed the study (Table 1).  The mean values for the pre-test throwing velocity as measured by the “turn and burn” drill were not significantly different between groups (Figure 2).  After the participation in the 6-week weighted ball throwing progression, the weighted ball group demonstrated a significant improvement for change in mean throwing velocity (mean change = 4.67 mph) within the 6 week period when compared to the control group (mean change = 1.00 mph)  (p = .05) (Table 2) (Figure 2).

Table 1.  Descriptive statistics for subjects.

Age (years)

Height (inches)

Weight (pounds)

Group 1 (Weighted Ball) (n = 9)

19.00 ± 1.323

73.22 ± 1.394

192.00 ± 27.060

Group 2 (Non-weighted) (n = 9)

19.67 ± 1.225

71.89 ± 1.764

196.22 ± 22.543

Figure 2.  Boxplots representing the mean throwing velocities for each group at pre-test and post-test.

Table 2.   Mean throwing velocities for each group at pre-test and post-test.

Pretest Velocity (MPH) Posttest Velcity (MPH) Change in velocity








*indicates a significant difference (p <.05)



The purpose of this study was to examine the effects of throwing under- and overweight baseballs on a pitcher’s throwing velocity in the turn and burn drill. DeRenne’s (1994) study of 225 college and high school pitchers is the only other study that has examined the integration of both over- and underweighted baseballs on throwing velocity. After 6 weeks of throwing under- and overweight baseballs, the weighted ball training group saw a significant increase in throwing velocity compared to the non-weighted ball throwing group. More Specifically the weighted ball throwing group saw an average increase of 4.67 mph (5.45%) and the non-weighted ball group only saw an average increase of 1 mph. This data is consistent with previous weighted ball research studies.

The findings above are similar to DeRenne’s (1994) study with 225 high school and college pitchers who threw a combination of both over- and underweighted baseballs for 10 weeks. Over the 10 week period the subjects in the over- and underweighted ball groups from DeRenne’s study saw approximately a 4%-6% increase. These results are similar to those that were found in this study. After a 6 week period while throwing both over- and underweighted baseballs, the over- and underweighted ball subjects from this study saw approximately a 5.45% increase (4.67 mph). The percentage increases from the two studies are very similar, but it needs to be taken into account that the testing methods between the two studies were different.  In DeRenne’s study pitchers were tested by pitching a regulation baseball, whereas in this study pitchers velocity was tested by doing the turn and burn drill with a regulation baseball. Further research needs to be conducted to determine the relationship between pitching velocity and turn and burn velocity.

The velocity increase observed for the weighted ball group is typical when compared to past studies. What also needs to be taken into account is the focus on throwing the balls with efficient throwing mechanics during the 6 weeks. This program was designed with a series of drills that put the body in different positions that are similar to different points in the pitching motion. According to a previous study by Werner et al (2008), body mass and 9 sequential and kinematic parameters related to pitching mechanics accounted for 68% of the difference in baseball throwing velocity. Throwing the ball efficiently will not only aid in the increase in ball velocity, but will also decrease in the amount stress put on the throwing arm.

Pitching a baseball has a lot of moving parts before the release of the baseball from the hand as mentioned by Werner et al (2008). It is important to think of the pitching delivery as chain of events that start at the feet and end with the throwing of the baseball with considerable force toward a target sixty feet six inches away. Throwing a baseball is one of the fastest motions in all of sports as the arm internally rotates at nearly 7,000°/second during the acceleration phase of throwing a baseball (Cressey, 2010). This amount of force puts a considerable amount of stress on the throwing shoulder and elbow. The rotator cuff muscles alone are not strong enough to decelerate that rate of acceleration, so it must take the 9 parameters described by Werner et al (2008) working efficiently to  not only help accelerate the arm, but to also help reduce some of the stress that is put on the throwing shoulder and elbow.

It must also be taken into consideration that during this study the pitchers were being coached on throwing the ball with proper mechanics while throwing over- and underweighted baseballs. All previous studies that have looked at pitching mechanics and their effect on throwing velocity have been done using regulation baseballs. Further research needs to be completed on the kinematic changes of throwing over- and underweighted baseballs.

In conclusion, oftentimes coaches find it difficult to develop programs that both increase pitching velocity while also decreasing stress being put on the throwing arm. Developing efficient mechanics both aid in increasing velocity and decreasing stress on the throwing arm. The addition of throwing under- and overweight baseballs with the specific drills from the 6 week program, not only create more arm strength and speed, but also teach the body how to throw a baseball efficiently.

Because of NCAA regulations the last two weeks of this study were not monitored by a coach. Athletes were required complete the last five sessions independently and the final testing day was then monitored.

Future studies should focus on the kinematic changes that may occur to the pitching motion while throwing weighted baseballs to determine if there is any additional stress placed upon the throwing arm when throwing under- and overweight baseballs. This study was also completed during the fall non-traditional season of NCAA division III pitchers, future research should include the effects of over- and underweighted baseball training during the season.


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