Youth Baseball Pitch Counts Vastly Underestimate High-effort Throws Throughout a Season

J Pediatr Orthop. 2020 Aug;40(7):e609-e615. doi: 10.1097/BPO.0000000000001520.


Background: The primary purpose of this study was to compare the number of pitches thrown by youth baseball players under the official league guidelines versus the number of "high-effort" throws recorded by a validated digital sensor worn by the players during a season.

Methods: In total, 11 and 12-year-old youth baseball players from a single league were provided an elbow sleeve and sensor to wear each time they threw a baseball for an entire baseball season. The sensor tracked total throws and pitch-equivalent high-effort throws for the season. Official pitch counts were collected at each game from the official scorekeepers.

Results: A total of 19 players participated in the study. The sensor-determined mean total throw count (1666.2±642.2) and mean high-effort throw count (576.9±329.3) per player were both significantly higher, P<0.0001 and P=0.02, respectively, than the mean official pitch count (168.1±122.4).

Conclusions: Our findings demonstrate that youth players make significantly more total throws and high-effort, or pitch-equivalent, throws, than what is recorded by the official pitch counts. Further research is needed to determine a safe annual "throw count" for young throwing athletes and to determine which types of throws, in addition to pitches, put youth throwers at risk for injury.

Level of evidence: Level IV.