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BackgroundStudies examining the evolution of shoulder and elbow range of motion (ROM) in baseball pitchers over a single season have yielded inconsistent results.PurposeTo 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 designCase-control study; Level of evidence, 3.MethodsBilateral 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.ResultsOn 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.ConclusionSignificant 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.

Mutations in the rpmB,G operon were observed for their effects on ribosome assembly in three strains of Escherichia coli. Inmutant strain TP28, the ribosomal proteins were synthesized at half the normal rate and this resulted in disturbances in ribosome assembly. This showed that base changes in the Shine-Dalgarno sequence caused a reduction in beta-galactosidase translation. A mobile element inserted into the coding sequence of mutant AM108 resulted in unbalanced protein synthesis although ribosome assembly was normal. Studies on strain AM90 showed that protein L33 does not regulate the operon.

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. [ABSTRACT FROM AUTHOR]