When Can Kids Throw a Curveball?

Want to ignite baseball passions perhaps even more than a Yankee-Red Sox or Dodger-Giant rivalry?

Ask the question “When should young pitchers throw a curveball?” and then stand back.

The basic concern is that the still developing bone and soft tissue structures in the shoulder and elbow may not be able to adequately handle the rotational forces needed to throw a curveball. A wicked curveball thrown early in a career could potentially lead to wicked damage and early termination of said pitching career.

Do scientific studies and articles offer any substantial help?

The USA Baseball Medical and Safety Advisory Committee has the recommendation that a curveball should not be thrown until age 14, with only fastballs and change-ups thrown before this age.

Why age 14? Most likely because most pitchers at this age have nearly full if not complete maturity of growth centers around the elbow and shoulder and thus these joints can better handle the forces of throwing a curveball.

• Now, not every child develops at the same point, and in pediatrics we are often trained not to use an absolute age to determine maturity, but rather to use certain milestone to better gauge individual development.
• A pretty solid (and simple) recommendation that maintain this spirit comes from a Major League team physician who states “Don’t throw breaking pitches until you nave shaved".
• The age or development-based recommendations are primarily based on baseball expert opinion and have no significant evidence-based supporting data.

On the other hand, a systemic review of published studies by Grantham et. al in Sports Health concluded that limited biomechanical and most epidemiologic data do not indicate an increased risk of injury when compared with the fastball in pitchers from Little League through professional ranks.

• The epidemiologic evidence to support limitations on the curveball is lacking rigor in study design
• The current biomechanical evidence (kinematic and kinetic analysis of the torso, shoulder, elbow and wrist) does not support limiting the use of curveballs at any level of baseball

         However, before one rushes off to the local diamond to teach the curveball to young throwers, I must share some other important conclusions:

• A young pitcher has a wicked curveball very likely will be perceived as a better pitcher and thus be asked to throw more often, leading to higher pitch counts which have been shown to contribute to  arm overuse injuries.

o   In my experience, anything that makes a young pitcher stand out (taller than peers, good control, stronger fastball) put more pressure on coaches and families to protect those talents and not let them be overused at too young an age.

• The “over the top” wrist snap motion routinely used to increase curveball spin may overload certain forearm supinator muscles, so training these muscle groups along with the shoulder rotator cuff muscles for the curveball.

o   Share this opinion, and would also recommend addressing any limitations in shoulder internal rotation range of motion that can also overload the elbow and wrist regions.

•  Do not underestimate the often unsung virtues of the change-up pitch. The authors found two studies found that throwing a changeup pitch reduced the incidence of elbow and/or shoulder pain and voiced support for USA Baseball’s recommendations to use the change-up to prevent arm injuries.

My bottom line: use stage of development, not simple a specific age, to help determine when a child is ready to throw the curveball. Realize that a good curveball sets a kid up for being asked to pitch more frequently, which can lead to overuse. Assessing shoulder, elbow, and arm strength and range of motion can reduce risk of injury when throwing a curveball.