1. Association of Player Demographics and Pitching Characteristics with Pitcher Injuries in Major League Baseball
Leslie Schwindel, MD; Vincent Moretti, MD; Brian Schwartz, MD; Mark Hutchinson, MD
University of Illinois at Chicago, Department of Orthopaedic Surgery – Chicago, IL
The injured population of pitchers was significantly older than uninjured pitchers (30.9 vs 29.1, p<0.01). There were also more starting pitchers in the injured group compared to the uninjured group (52.9% vs 39.8%, p<0.01). There was no difference between injured and uninjured pitchers based on average height (p=0.80), weight (p=0.34), BMI (p=0.30), or throwing side (p=0.72). Injured pitchers less frequently threw fastballs than uninjured pitchers (57.4% of pitches vs 60.2%, p=0.02) and had a slower average curveball velocity (75.9 mph vs 77.0, p<0.01). There was no difference (p>0.05) between injured and uninjured pitchers based on frequency of throwing cutter, slider, curveball, change-up, or split-finger pitches. There was similarly no difference (p>0.05) between injured and uninjured pitchers based on average throwing velocity of fastball, cutter, slider, change-up, or split-finger pitches.
INTRODUCTION
Tremendous forces are placed on the upper extremity during a maximum-effort baseball pitch, with generated torques and loads that approach the failure limits of surrounding tissues. Major League Baseball (MLB) managers and scouts often suggest that shorter or smaller athletes who pitch at high velocities are injury-prone and not durable for a career as a starting pitcher. Consequently, many talented young pitchers who fit these physical characteristics are lightly regarded and/or funneled into relief pitching roles early in their career.
OBJECTIVE
The goal of this study was to evaluate pitcher injuries in MLB and determine if any relationship with player demographics or pitching characteristics exists.
METHODS
The name of every player in MLB who appeared in at least one game as a pitcher during the 2012 season was gathered from official online MLB records and game summaries. Data on each player’s pitch selections and average velocities during the 2012 season was gathered from FanGraphs, an online baseball statistics and analysis archive. Data on pitcher injuries occurring during the 2012 season was gathered from MLB disabled list (DL) records. Demographic information for each pitcher was obtained from MLB player profiles. Recorded variables included player age, gender, height, weight, body mass index (BMI), throwing hand, and position (starting or relief pitcher). Statistical analysis was performed using Student’s t-test and chi-square test with a significance level of 0.05.
Table 2: Pitch characteristics based on area of injury
RESULTS
662 players made at least one appearance as a pitcher during the 2012 MLB season. 172 (25.98%) of these pitchers were on the DL for part of the season. Average pitcher age was 28.2 years (range ). All players were male. Average height, weight, and BMI were 74.6 inches (range ), lbs (range ), and 27.7 (range ), respectively. 474 (71.6%) pitchers threw right-handed and 188 (28.4%) threw left-handed. 286 (43.2%) pitchers started at least one game and 376 (56.8%) only appeared in relief.
Figure 1: Number of injured players based on area of injury
CONCLUSION
Over a quarter of MLB pitchers spent part of the 2012 season on the DL. Starting pitchers and older pitchers appeared to be prone to injury, but player height, weight, BMI, and throwing side were not risk factors. Interestingly, injured pitchers utilized less fastballs and threw slower curveballs, but whether these pitching characteristics led to injury or were the result of injury is not immediately clear. MLB teams and physicians looking to avoid injury may consider moving older or injury-prone pitchers to relief roles, encouraging fastball selection, and closely monitoring players with slow curveball velocities.
Figure 1: Pitcher characteristics (age, height, weight, BMI, dominant hand)