Use of the Reduced Impact Ball in Youth Baseball, Ages 5-12
USA Baseball Medical/Safety Advisory Committee
November 2008

Baseball is the second most commonly played team sport in the United States with approximately 8.6 million participants aged six to 17 participating each year.1 Safety has always been an important issue in youth baseball. Overall, injury rates appear to be quite low; however, given the large number of participants, even small reductions in the injury risk have considerable public health significance.

One area of controversy in youth baseball has been the use of the modified or soft baseball, but there has not been adequate research linking injury and equipment data. Accordingly, the USA Baseball Medical and Safety Advisory Committee conducted two national research projects to address both the ball and rates of injury. The first study assessed the injury rate in youth baseball, while the second assessed the effectiveness of the modified baseball during the 1997-1999 seasons.

Injury data was collected from Little League Baseball, Inc. insurance data from 1987-1996. For the ten-year period, there were 17,221,210 athletes ages 5-12 with 29,038 injuries resulting in an injury rate of 1.69 injuries per 1,000 participants. The second research project included three sources of national data from Little League Baseball, Inc.; 1) insurance injury reports, 2) participation numbers, and 3) a survey of equipment.3 Equipment information was collected from each of the approximately 5,050 leagues through an initial questionnaire to the league safety officers and by telephone follow-ups the final two years. The response rate averaged 97%. Given the size of the league (over two million participants annually) and the fact that it is national in scope, it represents one of the most significant sources on injuries in organized youth baseball.

In 1995 the Consumer Product Safety Commission (CPSC) estimated that 162,100 5-14 year-olds were treated in the emergency room for injuries incurred during organized and unorganized baseball, softball, and t-ball.4 Results indicated the most common cause of injury was ball impact, which accounted for 88,700 injuries, 55% of the total injuries. There were 47,900 (29.5%) injuries that involved ball impact to the head/neck area. CPSC concluded that a number of the ball injuries to the head/face could have been lessened in severity or prevented by the use of the softer balls. An earlier study by the CPSC found 88 baseball-related deaths to children ages 5-14 between 1973 and 1995, an average of four per year. Ball impact accounted for 68. Of these 68, 38 were ball impact to the chest, 21 to the head, and nine were to other areas.

Janda, et.al. studied the relative risk of fatal cardiac injury from various baseballs using both pigs and modified crash dummies.5,6 The research also involved looking at six different kinds of chest protectors. The researchers used two standard balls for controlled balls and six softer core balls for experimental balls. According to the researchers, the softer core balls alone showed little protective benefit, and may even have increased the amount of force that goes into the chest. It was also shown that chest protectors provided little protective benefit, and may have increased momentum. As a result, the authors concluded there is no proven way to prevent catastrophic cardiac injuries in youth baseball and soft-core baseballs may not differ from a standard baseball. The authors recommended that other techniques, such as preventive coaching, be implemented when trying to improve baseball safety. In a study with contrary results, Link, et. al., using a pig model, found that with safety baseballs, as compared with regulation balls, the likelihood of ventricular fibrillation was proportional to the hardness of the ball. The softest balls were associated with the lowest risk.7 The authors also stated in their conclusions that whether ventricular fibrillation occurred depended on the precise timing of the impact.

It has been speculated that the reduced impact or soft baseball may increase eye injuries by intruding more into the orbit. Vinger, et.al., stated that the potential for injury to the unprotected eye from soft baseballs is significant, but not greater than that from a regular baseball.8 The authors concluded that modified baseballs do not increase the potential for eye injury to the unprotected player.

Using a theoretical model to simulate the response of the head to a thrown ball, Crisco, et. al., wanted to determine the effect of lowering ball modulus (stiffness) and mass on the capacity to reduce impact injury.9 The researchers used four different ball models. This theoretical model suggested that a softer and lighter than traditional baseball would be the most likely ball model to minimize impact injuries because the ball consistently reduced all impact response variables studied. However, the authors also stated that since impact injury criteria for youths are presently not validated, the degree to which impact injuries may be reduced remains uncertain. They also indicated that soft balls have the potential to reduce catastrophic injury.

The results of the USA Baseball studies showed that ball injuries accounted for 15,266 injuries (52.6% of all injuries), with the batted ball accounting for 5,882, the pitched ball accounting for 5,609, and the thrown ball accounting for 3,775 (20.2%, 19.3%, and 13% of all injuries respectively). The body parts most injured by the ball were the face with 9,281, teeth with 3,025, head with 1,112, knee and ankle with 593, and the chest with 216. The only measure of severity was the type of injury associated with particular body parts. Fractures, dislocations, and concussions were considered the most severe and they accounted for 6,778 injuries or approximately 25% of all injuries. The USA Baseball three-year equipment study found that the reduced impact ball was effective in decreasing the risk of ball-related injury. All of the reduced impact balls (NOCSAE 1 and 2, see below) showed an average 29% reduction in ball-related injury risk. The protective effect of reduced impact balls was statistically significant for the Tee-Ball (5-8) and Minor (7-12) divisions, but not in the leagues with the more skilled player.

Injuries to young baseball players from being hit with an oncoming baseball, whether batted, pitched, or thrown, are to a great extent due to the player's unskilled response. As a result, reduced impact baseballs have become available to help reduce the force of impact when striking a player. There is a NOCSAE (National Operating Committee on Standards for Athletic Equipment) standard for youth baseballs. This standard specification establishes performance requirements in weight, compression load and stiffness (hardness), and coefficient of restitution for new youth baseballs as supplied by manufacturers. The standard has the following three levels: 1) designated for children with the lowest skill level, 2) designated for youths with moderate skill levels, 3) designated for youths with advanced skill levels.

Therefore, based on the research performed by USA Baseball and other investigators demonstrating that a reduced impact ball can decrease the incidence and severity of ball impact injuries to less skilled players aged 5-12, the USA Baseball Medical and Safety Advisory Committee recommends:

1. That youth baseball organizations adopt for their Tee-Ball and other "minor league" programs that are focused on skill development, reduced impact baseballs that meet NOCSAE standards levels 1 and 2.

2. This recommendation does not diminish the importance of teaching fundamental baseball skills and ball avoidance skills and techniques for batters.

3. Current scientific literature on the prevention of commotio cordis by chest protectors is not adequate and therefore, the effect of any equipment on the risk of chest impact death remains unsubstantiated at this time.

REFERENCES
1. Baseball and Softball Council: Baseball: A report on participation in America's National pastime. Sporting Goods Manufacturers Association 1996: 1-11.
2. USA Baseball Medical and Safety Advisory Committee: Injuries in Little League Baseball - 1987-1996. Submitted for publication 2001: 1-23.
3. USA Baseball Medical and safety Advisory Committee: Safety balls and face guards prevent injury in youth baseball: a cohort study. Submitted for publication 2001: 1-24.
4. Kyle SB. US Consumer product Safety Commission youth baseball protective equipment project final report. US Consumer Product Safety Commission 1996.
5. Janda DH, Ivan DC, Andrzeak DV, Hensinger RN: An analysis of preventive methods for baseball-induced chest impact injuries. Clinical Journal of Sports Medicine 1992; 2(3): 172-179.
6. Janda DH, Bir CA, Viano DC, Cassatta SJ: Blunt chest injuries: assessing the relative risk of fatal cardiac injury from various baseballs. Journal of Trauma-Injury Infection and Critical Care 1998; 44(2): 298-303.
7. Link MS, Wang PJ, Pandian NG, et al: An experimental model of sudden death due to low-energy chest wall impact (commotio cordis). New England Journal of Medicine 1998: 338(25): 1805-11
8. Vinger PF, Duma SM, Crandall J: Baseball hardness as a risk factor for eye injuries 1999: Archives of Opthalmology; 117(3); 354-358.
9. Crisco JJ, Hendee SP, Greenwald RM: The influence of baseball modulus and mass on head and chest impacts: a theoretical study. Medicine and Science in Sports and Exercise 1997: Vol.29(1): 26-36.