Student Well-Being

Study Finds Fatigue a Culprit for Increase in Youth-Pitcher Injuries

By Bryan Toporek — March 10, 2016 3 min read
  • Save to favorites
  • Print

What’s behind the increase in shoulder and elbow injuries among youth pitchers in recent years? According to a study presented Saturday at the American Orthopaedic Society for Sports Medicine’s Specialty Day, fatigue and overuse are contributing factors, as pitchers’ mechanics change as their pitch count increases.

The study examined 28 pitchers between the ages of 13 and 16, all of whom were asked to throw a 90-pitch simulated game. The authors recorded the velocity and accuracy of every pitch and assessed the pitchers’ shoulder range of motion both before and after the outing. In addition, they videotaped every 15th pitch to examine how the pitchers’ mechanics changed as the simulated game progressed.

As expected, pitchers became “progressively more fatigued and painful and pitched with a lower velocity as pitch number increased,” according to the study. Their hip and shoulder separation decreased as their pitch count went up, while their knee flexion at the release of the ball progressively increased. Following the outing, the total range of motion in their pitching shoulders significantly increased, too.

“Through our analysis of pitching mechanics, it was noted that core and leg strength may be a key component of fatigue and ultimately injury in pitchers,” said Dr. Robert Chalmers, the lead author of the study, in a statement. “As pitchers became fatigued, trunk rotation timing began to falter and pain increased. We hope that with additional research, we can work towards programs to help build strength and prevent these shoulder and elbow pitching injuries.”

Concern over youth-pitcher workloads has grown in recent years, leading to initiatives aimed at curtailing overuse. In November 2014, Major League Baseball debuted its “Pitch Smart” program, which offered recommendations on the daily maximum of pitches youths of each age should throw, along with the recommended amount of required rest for those pitchers based on how many times they threw the ball during their previous outing.

MLB `Pitch Smart`
Create your own infographics

Earlier that year, renowned orthopedic sports surgeon Dr. James Andrews warned against having youth pitchers play year-round baseball, suggesting it was the No. 1 cause for the rise in pitchers of all ages undergoing Tommy John surgery. In an interview on MLB Network Radio’s “Power Alley,” he said, “These young kids are now maturing their bodies so quickly, their ligament is developmental, and it’s not strong enough to keep up with their bodies. So, they’re tearing it in the high-velocity throwers at a young age. And that’s really the big problem.”

Last winter, the Colorado High School Athletics Association approved a proposal that required rest days based on the number of pitchers a player throws in a day, either in a practice or a game, beginning in 2016. According to, the Alabama High School Athletic Association followed suit last October, requiring varsity pitchers to rest three calendar days after throwing 76 to 120 pitches in one day. Junior varsity pitchers aren’t allowed to exceed 100 pitches in a day under the new rule, which goes into effect in 2017, while junior high and middle school players are restricted to no more than 85.

While more research is needed to determine if there’s a particular threshold of pitches in a given day that youth pitchers should not exceed, this latest study certainly suggests bloated workloads could contribute to shoulder or elbow injuries. Youth-baseball coaches should remain mindful of injury risk when tasking pitchers with long outings, particularly if their state’s athletic association has yet to establish a pitch-count limit.

Related Tags:

A version of this news article first appeared in the Schooled in Sports blog.