Zajac, John M.

Context: There is need for an up-to-date comprehensive review of baseball interval throwing programs in the literature. Objective: To (1) understand the origin and basis of interval throwing programs; (2) evaluate the content of programs in the peer-reviewed literature including target audience, initiation criteria, throwing specifics, arm care, and performance evaluation metrics; (3) classify these variables as well defined, ambiguous, or missing; and (4) analyze variability in key aspects including starting criteria, length, progression, and completion criteria. Data Sources: Medline, Embase, Cochrane Reviews, Web of Science, and Scopus Study Selection: The full text of studies, in English, had to be available. Included studies had to contain a complete interval throwing program designed for baseball players. Study Design: Systematic review. Level of Evidence: Level 4. Data Extraction: Initial screening was conducted based on article title and abstract. Full text of the remaining articles was evaluated for fulfillment of inclusion criteria. Results: Nine studies initially met inclusion criteria. The programs’ comprehensiveness was poor, with a mean Interval Throwing Program Checklist score of 20 (range 14-23) on a scale of 0 to 30. There were a variety of components, including progressive long toss, weighted ball, and throwing mechanics exercises. The programs identified had significant heterogeneity in duration, intensity, progression, and focus. Overall, there was a significant lack of attempts at validation or formal study of efficacy for published throwing programs. Conclusion: Current published interval throwing programs are mostly variations of an original program published many years ago and were based on principles of progressive loading with pain as sign of injury that should be monitored carefully. However, these programs have minimal clinical validation and objective measures to quantify their effectiveness. This work identifies several limitations in the current literature and can serve as a foundation for future development of evidence-based interval throwing programs.

Background: Loss of upper and lower extremity range of motion (ROM) is a significant risk factor for injuries in professional baseball players. Purpose/Hypothesis: The purpose was to determine changes in ROM in professional baseball players over the course of a single season and their careers. We hypothesized that pitchers and position players would lose ROM, specifically total shoulder motion (total ROM [TROM]) and hip internal rotation (IR), over the course of a season and their careers. Study Design: Case series; Level of evidence, 4. Methods: Upper and lower extremity ROM measurements were recorded during pre-, mid-, and postseason on all professional baseball players for a single organization between 2011 and 2018. ROM measurements were compared for pitchers and position players over the course of the season and their careers. Also, ROM measurements over the pre-, mid-, and postseason were compared between pitchers and position players. Results: A total of 166 professional baseball players (98 pitchers, 68 position players) were included. Pitcher hip external rotation (ER; P < .001), IR ( P = .010), and TROM ( P < .001) for lead and trail legs decreased over the course of the season. Pitcher shoulder ER ( P = .005), TROM ( P = .042), and horizontal adduction ( P < .001) significantly increased over the course of the season. Position player shoulder flexion ( P = .046), hip ER ( P < .001, lead leg; P < .001, trail leg), and hip TROM ( P = .001; P = .002) decreased over the course of the season. Position player shoulder ER ( P = .031) and humeral adduction ( P < .001) significantly increased over the course of the season. Over the course of pitchers’ careers, there was decreased shoulder IR ( P = .014), increased shoulder horizontal adduction ( P < .001), and hip IR ( P = .042) and hip TROM ( P = .027) for the lead leg. Position players experienced loss of hip TROM ( P = .010, lead leg; P = .018, trail leg) over the course of their careers. Pitchers started with and maintained more shoulder ER and gained more shoulder TROM over a season as compared with position players. Conclusion: Pitchers and position players saw overall decreases in hip ROM but increases in shoulder ROM over the course of the season and career.

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.

Background: Studies examining the evolution of shoulder and elbow range of motion (ROM) in baseball pitchers over a single season have yielded inconsistent results. Purpose: To evaluate shoulder and elbow ROM in Major League Baseball (MLB) pitchers over a single season and to assess for correlations between these changes and measures of a pitcher’s workload. Study Design: Case-control study; Level of evidence, 3. Methods: Bilateral shoulder ROM (internal rotation [IR], external rotation [ER], and total range of motion [TROM]) was assessed in 92 MLB pitchers pre- and postseason. Shoulder forward flexion (FF) was measured in 64 pitchers, horizontal adduction (HA) was measured in 87 pitchers, and elbow ROM was measured in 86 pitchers. Data collected included demographics (age, height, weight, and body mass index) and measures of workload for pitchers (pitches thrown, innings pitched, and mean fastball velocity). Pitchers were not specifically excluded if they had an injury during the season but had recovered and were actively pitching at the time of postseason measurements. The change in motion from pre- to postseason was measured and the associations with player demographics and workload were calculated by use of the Pearson correlation coefficient. Results: On average, pitchers demonstrated an increase in dominant shoulder ER from 118.8° to 125.4° ( P < .001) and TROM from 173.1° to 181.7° ( P < .001). HA was increased by an average of 15.7° ( P < .001). The average shoulder IR ( P = .189), FF ( P = .432), and elbow ROM (flexion, P = .549; extension, P = .185) remained similar over the span of the season. Average glenohumeral IR deficit did not increase. Pitcher demographics and measures of throwing workload (total pitches thrown, innings pitched, mean fastball velocity) were not significantly correlated with changes in shoulder or elbow ROM. Conclusion: Significant increases in dominant shoulder ER, TROM, and HA were identified in MLB pitchers over the course of a single baseball season. These ROM changes were not correlated with measures of pitching workload.

Background: Although restricted hip range of motion (ROM) is associated with an increased risk for injuries in baseball players, the evolution of hip ROM over the season remains undefined. Hypothesis: Hip ROM profiles would be symmetric between hips and positions (pitchers vs position players) but would decrease from preseason to postseason. Additionally, it was hypothesized that this decrease in motion would correlate with workload. Study Design: Cohort study; Level of evidence, 2. Methods: Bilateral hip ROM was assessed in 96 professional baseball players (54 pitchers, 42 position players) preseason and postseason. ROM comparisons were made between lead and trailing hips, pitchers and position players, and preseason and postseason measures. The change from preseason to postseason was correlated with player demographics and measures of workload for pitchers and position players. Results: Preseason hip ROM was symmetric between hips; however, pitchers demonstrated increased preseason lead hip internal rotation (IR) ( P = .018) and bilateral hip total ROM (TROM) ( P < .020) compared with position players. From preseason to postseason, position players lost 7° of external rotation (ER) ( P ≤ .005 ). In pitchers, the loss of IR correlated with increased pitches ( P = .016) and innings ( P = .037), while the loss of ER ( P = .005 ) and TROM ( P = .014) correlated with increasing mean fastball velocity. Workload for position players did not correlate with motion loss. Conclusion: Symmetric hip ROM profiles should be anticipated in baseball players; however, pitchers may have increased preseason IR and TROM and postseason ER and TROM relative to position players. Although loss of motion correlated with workload in pitchers, this was not the case for position players. Hip motion should be monitored over the course of the season. This is particularly true for pitchers who lose IR as workload increases, which may place them at a greater risk for injuries.

Purpose The primary aims of this work were to (1) describe normal range of motion (ROM) profiles for elite pitchers, (2) describe the characteristics of shoulder and elbow injuries in professional pitchers over a 6‐year period in one Major League Baseball organization, and (3) identify ROM measures that were independently associated with a future shoulder or elbow injury. Methods Over 6 seasons (2010‐2015), a preseason assessment was performed on all pitchers invited to Major League Baseball Spring Training for a single organization. ROM measures included shoulder flexion, horizontal adduction, external rotation (ER), internal rotation, as well as elbow flexion and extension, were measured for both the dominant and nondominant arm, and total range of motion and deficits were calculated. All noncontact shoulder and elbow injuries were identified. Using multivariate binomial logistic regression analysis to control for age, height, weight, and all other ROM measures, the factors associated with an increased risk of subsequent shoulder or elbow injury were identified. Results A total of 53 shoulder (n = 25) and elbow (n = 28) injuries occurred during 132 pitcher seasons (n = 81 pitchers). The most significant categorical risk factor associated with increased elbow injury rates was the presence of a shoulder flexion deficit >5° (odds ratio [OR] 2.83; P = .042). For continuous variables, the risk of elbow injury increased by 7% for each degree of increased shoulder ER deficit (OR 1.07; P = .030) and 9% for each degree of decreased shoulder flexion (OR 1.09; P = .017). None of the measures significantly correlated with shoulder injuries. Conclusions Preseason shoulder ER and flexion deficits are independent risk factors for the development of elbow injuries during the upcoming season. Although prior work has supported the importance of reducing glenohumeral internal rotation deficits in pitchers, this study demonstrates that deficits in shoulder ER and flexion are more significant predictors of subsequent elbow injury. Level of Evidence Level III, retrospective comparative study.