421 FO62 – Development of a protocol to evaluate baseball pitcher’s workload and prevention of injury

Background Pitch counts are only one measure of the true workload in baseball pitchers. Newer research indicates total workload and prevention of injury must include additional factors. Thus, current workload monitoring systems may be considered inadequate. Objective Develop a novel method to determine baseball pitchers' workload to provide an implementable process for prevention of throwing related injuries. Design Prospective observational study Setting Academic medical center Participants Pitchers aged 13–18 during the 2019 to 2023 seasons Assessment of Risk Factors Pitching related injuries, workload, pitching velocity, intensity, and pitch counts Main Outcome Measures Workload, calculated by multiplying volume of total gameday pitches by intensity, was the primary measure. Intensity was determined by maximum pre-season velocity compared to game velocity of pitches thrown. Velocity was measured during a preseason practice and the first 10 pitches of each inning. Total gameday pitches included bullpen, warm-up, and game pitches. Results There were 313 pitcher outings, 11 pitching related injuries and 24,228 pitches thrown. Gameday pitch counts ranged from 19 to 219 (mean 77.5; SD 41.0). Velocity ranged from 75.3 to 137.9 km/hour (mean 114.8 ± 9.3 km/hour). Intensity ranged from 0.7 to 1.3 (mean 1.0 ± 0.08). The mean workload for all pitchers was 74.7 ± 40.1. Risk factors significant for injury included: throwing at a higher velocity in game (p=0.001), increased intensity (e.g. an increase in average velocity thrown from preseason to in-season; p <0.001), and being an older pitcher (p = 0.014). There was no significant association with injury and total pitches thrown (p = 0.749). Injured pitchers accumulated an increased workload of 16.7% (p = 0.716). Conclusions High School Baseball pitchers throwing at a higher velocity, intensity, and older age are at greater risk for injury. Thus, these athletes may require closer observation for prevention of pitching related injuries.