Early single sport specialization does not improve pitching velocity, motion, strength, or utilization in high school baseball pitchers.

Background: The impact of single-sport specialization on performance and injury risk in youth and adolescent athletes remains debated. The purpose of this study was to determine the incidence of single-sport specialization and its association with pitch velocity, pitcher utilization, range of motion, strength, and injury history. Methods: High school pitchers in the Northeastern, Southeastern, Midwestern, and Western Regions of the United States were prospectively recruited. Prior to the season, pitchers were surveyed about their basic demographics, sport participation history, and injury history. At this timepoint, a standardized physical examination was performed and max pitch velocity was measured. They were then prospectively followed over the ensuing high school season, where pitch utilization and counts were followed and injuries were tracked. Results: Across the study, 115 pitchers were recruited, of whom 53% played baseball as their only sport and 47% played other sports. Single- position specialization within baseball was uncommon as 90% of athletes played positions other than pitcher. There were no differences in range of motion, strength, or pitch velocity between multisport athletes and single-sport specialists. Within the multisport group, 26% reported a history of injury, while 38% of the single-sport specialists reported a history of injury (P = .179). There were no significant differences in pitcher utilization between multisport athletes and single-sport specialists. Only a single prospective injury occurred in the 115 players. Conclusion: Although single-sport specialization is common, nearly half of all high school pitchers in this study were multisport athletes. While injury history was generally similar between the two groups, single-sport baseball players did not have the following: improved motion, increased strength, higher ball velocity, or greater pitching volumes during the high school baseball season compared to multisport athletes. Accordingly, single-sport specialization did not have a competitive advantage for these high school pitchers based on the performance factors studied. Further prospective studies are necessary to understand the association between single-sport specialization and injury risk in high school baseball players.

Changes in Elbow Stress and Ball Velocity During Reduced Effort Pitching: A Marker-Based Motion Capture Analysis.

BACKGROUND: Baseball pitchers often participate in throwing programs that involve throwing at reduced effort levels to gradually increase the amount of stress experienced across the elbow. It is currently unknown how reduced effort pitching compares with maximum effort with respect to elbow stress and ball velocity. PURPOSE/HYPOTHESIS: The purpose was to determine the correlation between elbow stress and ball velocity with reduced effort pitching. We hypothesized that decreased perceived effort would disproportionately correlate with elbow stress and ball velocity. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten healthy male high school baseball pitchers threw 5 pitches from a regulation pitching mound at 3 effort levels: maximum effort, 75% effort, and 50% effort. Elbow stress, specifically elbow varus torque, was calculated for all pitches using a validated marker-based 3-dimensional motion capture system. Ball velocity was measured using a Doppler radar gun. Intrathrower variability was calculated for each effort level. RESULTS: Elbow stress and ball velocity decreased with reduced effort throws (P < .001 and P = .003, respectively). However, the reductions in elbow stress and ball velocity were not proportional. At 75% effort throws, elbow stress measured 81% (intraclass correlation coefficient [ICC], 0.95), and ball velocity measured 90% (ICC, 0.80) of maximum, respectively. At 50% effort throws, elbow stress measured 75% (ICC, 0.93), and ball velocity measured 85% (ICC, 0.87) of maximum. Intrathrower reliability was excellent for elbow stress and ball velocity, with all ICCs ≥0.80. CONCLUSION: Pitching at a reduced effort level resulted in decreased elbow stress and ball velocity. However, for every 25% reduction in perceived effort, elbow stress decreased by a mean 13%, and ball velocity decreased 7.5%. When baseball pitchers attempt to throw at a reduced effort of maximum, throwing metrics do not decrease proportionately. CLINICAL RELEVANCE: While pitching at a reduced effort of maximum decreases elbow stress and ball velocity, the decrease is not proportional, subjecting the elbow to more stress than intended. This has significant clinical importance to pitchers, coaches, and medical professionals in the setting of injury prevention and return to sports.

Are Wearable Sensors Valid and Reliable for Studying the Baseball Pitching Motion? An Independent Comparison With Marker-Based Motion Capture.

BACKGROUND: In recent years, the prevalence of medial ulnar collateral ligament injuries has increased in throwers of all ages and skill levels. The motusBASEBALL sensor possesses an inertial measurement unit (IMU) that has been developed and applied to the throwing arm to allow for measurements of several objective parameters, which may prove beneficial for monitoring, rehabilitation, and injury prevention in the throwing athlete. However, the reliability, consistency, and validity of the IMU have not been independently assessed. PURPOSE: To evaluate the reliability, consistency, and validity of the motusBASEBALL sensor compared with the historic gold standard of marker-based motion capture. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 10 healthy male baseball athletes with varsity-level high school experience volunteered to participate in this study. Participants were fitted with 37 retroreflective markers for motion capture and the motusBASEBALL IMU sensor. Participants threw 5 fastballs at maximum effort, with measurements recorded simultaneously by motion capture and the IMU. Arm slot, arm speed, arm stress, and shoulder rotation were measured and compared. RESULTS: Of the 4 metrics generated by the IMU, significant differences were found for 3 of the throwing metrics compared with motion capture including arm slot (5.0°± 6.1°; P = .037), elbow varus torque (9.4 ± 12.0 N·m; P = .037), and shoulder rotation (6.3°± 6.1°; P = .014). Arm speed did not demonstrate a statistically significant difference (29.2 ± 96.8 rpm; P = .375). The IMU consistently underreported pitching performance values. Shoulder rotation exhibited excellent reliability with <5° of error, and arm slot demonstrated good reliability with <10° of error. Arm stress and arm speed were less reliable. CONCLUSION: The IMU was not accurate or valid for arm slot, arm stress, and shoulder rotation compared with marker-based motion capture. It was relatively accurate for arm speed. Despite its lack of validity, it was consistent and reliable for arm speed and shoulder rotation and relatively reliable for arm slot and arm stress. Caution should be used when comparing values provided by this IMU to the gold standard of marker-based motion capture. CLINICAL RELEVANCE: IMU technology has potential to be used in monitoring, rehabilitation, and injury prevention in throwing athletes if valid. This study demonstrates that the values provided by the IMU should not be considered equivalent to those generated by the gold standard of marker-based motion capture; however, there may still be a role for this technology when relying on its internal consistency for intrathrower comparisons and tracking.