Relationship Between Pitching a Complete Game and Spending Time on the Disabled List for Major League Baseball Pitchers

Effect of Weather and Game Factors on Injury Rates in Professional Baseball Players

BACKGROUND

Injury rates in baseball players of all ages are increasing. Identifying modifiable risk factors is paramount to implementing injury prevention programs.

PURPOSE/HYPOTHESIS

The purpose was to evaluate the influence of weather (temperature, humidity, atmospheric pressure, and heat index) and game factors (start time, duration, single vs doubleheader) on injury rates in professional baseball players. We hypothesized that colder temperatures would be associated with significantly more injuries per game.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This was a retrospective database study. Two data sets were combined: 1 containing all injuries in Major and Minor League Baseball between 2011 and 2017 and 1 containing all games played in Major and Minor League Baseball during the same period to determine the number of injuries per game. Temperature, humidity, atmospheric pressure, and heat index were determined for each game using the data from the US Environmental Protection Agency. Additional game variables included the level of play, the turf type (natural vs artificial grass), the stadium type (open vs dome vs retractable), the game start time, the game duration, and whether the game was a doubleheader. Then, a multivariate analysis was conducted to determine which factors were associated with the number of injuries per game.

RESULTS

In total, our analysis included 33,587 injuries and 76,747 games. A total of 25,776 (33.6%) games contained an injury, and 41% of injuries occurred as multiples per game, with up to 9 injuries per game. The multivariate analysis identified significant associations between game duration and injuries per game (P < .001; effect size, 0.013) and the level of play and injuries per game (P < .001; effect size, 0.011). There were significant associations between the venue type (P < .001), the game start time (P < .001), humidity (P < .001), the turf type (P = .016), and barometric pressure (P = .031); however, the effect size for each was <0.001, suggesting that these factors are clinically unimportant. Our overall model produced an R² of 0.04, indicating that these variables only predicted 4% of the variance in injury risk.

CONCLUSION

In professional baseball, the weather is not associated with injury risk; however, game duration may contribute to injury risk.

Do Professional Baseball Players With a Higher Valgus Carrying Angle Have an Increased Risk of Shoulder and Elbow Injuries?

Background:

There are many risk factors for shoulder and elbow injuries in professional baseball pitchers. The elbow carrying angle has not been studied as a potential risk factor.

Purpose/Hypothesis:

The aim of this study was to determine whether elbow carrying angle is a risk factor for shoulder or elbow injuries in professional baseball pitchers. We hypothesized that pitchers with a higher elbow carrying angle would be less likely to sustain an injury during the season than pitchers with a lower elbow carrying angle.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

All professional pitchers for a single baseball club during the 2018 season had the carrying angle of both elbows measured at spring training by a single examiner. The pitchers were followed prospectively throughout the season. Shoulder and elbow injuries were recorded prospectively.

Results:

A total of 52 pitchers (21 [40%] Major League Baseball and 31 [60%] Minor League Baseball) were included. During the season, 23 (44%) pitchers became injured. The mean carrying angle in the throwing arm was 12.5° ± 4.2° versus 9.9° ± 2.8° in the nonthrowing arm (P < .001). Comparing the injured and noninjured groups, there were no differences in level of play (P = .870), throwing hand dominance (P = .683), batting hand dominance (P = .554), throwing-side carrying angle (P = .373), nonthrowing-side carrying angle (P = .773), or side-to-side difference in carrying angle (P = .481).

Conclusion:

The elbow carrying angle was not associated with an injury risk during a single season in professional baseball pitchers.

Professional and Amateur Pitchers' Perspective on the Ulnar Collateral Ligament Injury Risk

Background

Medial ulnar collateral ligament (UCL) injury is increasingly prevalent in professional baseball pitchers, and significant research has been devoted to understanding the risk factors and prevention strategies associated with it. To date, no study has investigated what the players themselves believe causes and prevents the injury.

Purpose

To evaluate the opinions of UCL injuries among pitchers, including professional athletes.

Study Design

Cross-sectional study.

Methods

A total of 214 baseball pitchers (45 high school/college, 169 Major League Baseball [MLB]/Minor League Baseball) completed a 52-item questionnaire designed to evaluate their opinions on the cause of UCL injuries, injury prevention, and Tommy John surgery. Overall, 51 of the 214 pitchers had previously experienced a UCL injury. The frequency of the selection of each answer option was measured. Additionally, chi-square tests were used to compare (1) responses between professional and nonprofessional pitchers and (2) responses between pitchers with and without a previous UCL injury.

Results

Only 45% of pitchers thought that UCL injuries are avoidable in MLB. Additionally, 55% of pitchers with a UCL injury had a history of elbow injuries as an adolescent/child, compared with 18% in the uninjured group (P < .0001). Also, 72% of all surveyed pitchers agreed that fatigue over the course of a season increases the risk of UCL injuries, and the majority of pitchers agreed that inadequate rest from throwing both during the off-season (61%) and the season (59%) increases the risk of UCL injuries. Moreover, 59% of pitchers believed that a 6-man starting rotation would decrease the incidence of UCL injuries. Professional and nonprofessional pitchers significantly differed (P = .005) in the type of pitch most prone to causing UCL injuries.

Conclusion

Pitchers with a previous childhood elbow injury had a significantly higher incidence of UCL injuries during their adult career, suggesting possible predisposition to UCL injury and warranting further research. Fatigue and inadequate rest were of greatest concern among all pitchers for an increased risk of UCL injuries. Understanding and acknowledging the opinions that players have regarding UCL injuries are important to improve UCL education, prevention, and treatment.