Paper
Weighted Ball Velocity Throwing Programs Are Effective. Are the Benefits Worth the Risk?
Published Mar 11, 2020 · Jason L. Zaremski
Clinical Journal of Sport Medicine
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Abstract
With springtime around the corner, spring sports are in the air! Baseball and softball seasons, for instance, have begun in southern states, and northern states will see pitchers and catchers reporting in no time!However, with the start of a new season comes the risk of throwing injuries. Previous data was suggested that more throwing injuries occur in the preseason and early season than in the later stages of a baseball season. Because of the large number of overuse throwing injuries, in particular at the youth and high school levels, safety guidelines were adopted that included pitch count and rest day restrictions in an attempt to reduce injuries. However, even with robust data, increasing media coverage of pitch counts, and increasing awareness in the general public, there is concern there has not been a reduction in overuse throwingrelated injuries. Thus, there must be additional explanations for this lack of decrease in throwing injuries even with the implementation of throwing safety guidelines. One possible explanation is the interest and rise in weighted ball velocity (WBV) throwing programs. When entering a search for “weighted ball velocity throwing programs” into an internet search engine (such as www.google.com or www.bing.com), there are thousands of results that include numerous videos and advertisements on how to purchase weighted balls and participate in these training programs. However, there are many unsubstantiated claims with varying WBV throwing programs that create confusion to parents, coaches, and athletes and is reason to approach these programs with caution. Thus, due to the rising interest in this type of throwing training program, this editorial will explore WBV throwing programs as a possible contributor to this lack of reduction of throwing injury prevention. A recent study byReinold et al assessed pretest and post-test throwing velocity in 38 13to 18-year-old baseball pitchers. Data points included shoulder and elbow passive range of motion, shoulder strength, elbow varus torque, and shoulder internal rotation velocity. The weighted ball throwing program group participated 3 times per week using balls varying from 2 to 32 ounces, whereas the control group used a standard 5-ounce baseball. Results indicated a statistically significant 3.3% increase in velocity and an increase of 4.3 degrees of shoulder external rotation over the 6 weeks study period. However, in addition to the increase in velocity and increase in shoulder external rotation was an increase in injury rate by 24%.No pitchers in the control group sustained injuries. Another recent baseball study analyzing 17 collegiate and professional baseball pitchers sought to determine whether a 6-weeksWBV throwing program increased pitch velocity and any changes in ball speed and arm kinetics and/or kinematics. Using motion capture before and after the six-week training program, results indicated 9 pitchers increased their throwing velocity, whereas 8 did not. In the supplemental data, the average increase in throwing velocity was 2.1 miles per hour (mph) and decrease in the decreased velocity group was 2.4 mph. In the group that did increase their throwing velocity, maximum elbow medial force increased 32 N as opposed to a decrease of 14 N in the group that decreased throwing velocity during the arm cocking/ acceleration phase, although this data was not statistically significant. Similarly, during the arm cocking/acceleration phase of pitching, the increased velocity group saw a rise of maximum elbow varus torque of 4 N-m as opposed to a decreased of 5 N-m in the decreased throwing velocity group. Furthermore, a biomechanical study of 25 high school and collegiate baseball players using slightly underweight and overweight baseballs and motion capture was recently published. The data indicated that ball velocity increased the most with underweight balls; and kinetic and kinematic data did not significantly alter throwing arm kinetics. It is interesting to note that Flesig and colleagues tested pitchers in this study on a mound and flat-ground. Flatground throws with overweight balls lead to greater shoulder internal rotation velocity and elbow varus torque. Hence, this type of training exercise (flat ground WB throws) increased stress, and can lead to injury if used too frequently. Interestingly, one systematic review indicated that there were no negative effects using overweight or underweight balls with respect to injury risk. Thus, there is a lack of consistency in the literature with the usage of overweight or underweight balls with respect to injury risk. There have been other studies inquiring whether WBV throwing programs are successful at increasing throwing velocity. Two recent systematic reviews analyzed a group of studies published in the past 50 years, one in 2009 and one in 2019. In Caldwell et al.’s systematic review 6 of the 9 studies, ball velocity increased from 2.1 to 11.2 mph. Three Studies reported no significant difference in ball velocity. The authors concluded that while WBV throwing programs do seem to result in increased velocity, the long-term safety effects of using this training modality are not known at this time. From the Department of Orthopaedics and Rehabilitation, University of Florida,
Weighted ball velocity throwing programs can increase throwing velocity and shoulder external rotation, but may increase injury rates by 24%.
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