Unaccounted Workload Factor: Game-Day
Pitch Counts in High School Baseball Pitchers – An Observational Study
Zaremski
JL, Zeppieri G, Jones DL, Tripp BL, Bruner M, Vincent HK, Horodyski M.
Orthop J Sports Med. 2018; 6(4):2325967118765255
Take Home Message:
Pitch counts for baseball pitchers typically only include those completed as
part of regulation play. Warm-up and bullpen pitches should be considered in
total pitch counts to better capture actual workload during a game.
Sports medicine researchers have established that injuries to the upper extremity as a result of
repetitive throwing are frequent in high school baseball pitchers. Risk
factors, such as high pitch counts and poor pitching mechanics, have been
identified and baseball regulating bodies have enacted recommendations and
policy to aid in protecting pitchers from injury. However, the prevalence of
injuries has not declined; therefore, warm-up and bullpen activity may present
repetitions that increase total pitch count but to date have not been considered.
The authors hypothesized that current pitch counts (regulation pitches) are
underrepresented by up to 30-40% and many pitches likely occur during warm-up and bullpen
activity. Additionally, the authors postulate there would be highly variable
pitch counts during bullpen activities. For this observational study,
researchers collected counts for all pitches thrown from a mound for 34 high
schools over the course of one competitive season (February to May). Pitches
from a mound included those completed while in the bullpen during warm-up,
between innings, and during innings. A total of 13,769 pitches were tallied
over the collection period for 115 varsity starting pitcher outings. During
this time, no pitcher violated Major League Baseball’s (MLB) age-recommended
game pitch count of 105 pitches. Bullpen and warm-up activity increased the
average pitch count to 119.7 pitches per game compared to 68.9 during
regulation play. Furthermore, compared to pitch counts during regulation play,
bullpen and warm-up activity increased the total pitch volume by 42% thereby
causing approximately 70% of the 115 outings over the 105-pitch count threshold
deemed appropriate by the MLB. As hypothesized, bullpen activity was variable
among pitchers with a range of 11 pitches. Bullpen pitches were also positively
related to total pitch volume for the outing; meaning the higher the pitch
count during bullpen work, the higher the total game-day pitch count.  
The authors revealed a potential hidden threat to safe training volumes
for high school baseball pitchers and emphasized that a sudden increase of
training load may increase an athlete’s risk for injury. It is imperative that
clinicians are cognizant that a pitcher’s game-day pitch count represents only
a portion of their total physical load during any given game. An ineffective or
weak kinetic chain may further compound this issue. Additionally, this study
highlights a need to reexamine pitch count recommendations made by baseball
regulating bodies. The MLB’s recommendation for the age group in this study was
105 pitches per game; meaning only
those pitches thrown for a ball or strike appear to be included in that
recommendation. As other regulating bodies and sports medicine organizations
develop best practices and recommendations for injury prevention, a common
method for determine appropriate workload must be established.
Questions for Discussion: Do you track pitch volume for purposes of quantifying workload? Do you
factor in bullpen or warm-up activity when determining appropriate throwing
workload volume for training or rehabilitation?
Written
By:  Laura McDonald
Reviewed
by: Steve Thomas
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