High School Baseball Pitchers Research Articles

Associations Between Pelvis, Trunk, and Shoulder Girdle Muscle Activity; Age; and Scores During the Closed Kinetic Chain Upper Extremity Stability Test in Baseball Pitchers

OBJECTIVE: To evaluate associations between muscle activity, age, and scores on the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST). DESIGN: Quasi-experimental. METHODS: Pelvic, trunk, and shoulder girdle surface electromyography (sEMG) and kinematic data were measured in 21 high school and college male baseball pitchers (17.4 ± 2.0 years, 184.4 ± 5.7 cm, 78.4 ± 14.2 kg) while they performed the CKCUEST. Mean sEMG data were computed while in sole support on the throwing-arm side (TS) as the glove-arm side (GS) was horizontally translating. Correlations and local regressions were used to assess associations and general patterns between mean sEMG data, age, and scores. RESULTS: TS serratus anterior, TS external oblique, GS serratus anterior, and TS gluteus medius had the highest mean sEMG data. Low-to-high significant correlations were found between proximal muscle groups. Correlations with the highest magnitudes in descending order were TS external oblique and TS gluteus maximus, TS external oblique and TS serratus anterior, and GS external oblique and TS gluteus medius. Small significant associations were observed between other muscle groups and age; there were no associations between muscle activity and test performance. CONCLUSION: Associations were observed between mean muscle activity among muscle groups and age but not test outcome. JOSPT Open 2024;2(4):297-305. Epub 7 June 2024. doi:10.2519/josptopen.2024.1023

Kinematic Modeling of Pitch Velocity in High School and Professional Baseball Pitchers: Comparisons With the Literature.

Kinematic parameters predictive of pitch velocity have been evaluated in adolescent and collegiate baseball pitchers; however, they have not been established for high school or professional pitchers. To create multiregression models using anthropometric and kinematics features most predictive for pitch velocity in high school and professional pitchers and compare them with prior multiregression models evaluating other playing levels. Descriptive laboratory study. High school (n = 59) and professional (n = 337) baseball pitchers threw 8 to 12 fastballs while being evaluated with 3-dimensional motion capture (480 Hz). Using anthropometric and kinematic variables, multiregression models for pitch velocity were created for each group. A systematic review was conducted to determine previous studies that established kinematic models for ball velocity in youth, high school, and collegiate pitchers. Leg length was predictive of pitch velocity for high school and professional pitchers (P < .001 for both). When compared with previously established models for pitch velocity, almost all groups were distinct from one another when assessing age (P maximum < .001), weight (P max = .0095), and pitch velocity (P max < .001). Stride length was a significant predictor for the youth/high school pitchers, as well as the current study's high school and professional pitchers (P < .001 for all). Maximal shoulder external rotation (collegiate: P = .001; professional: P < .001) and maximal elbow extension velocity (high school/collegiate: P = .024; collegiate: P < .001; professional: P = .006) were shared predictors for the collegiate and current study's professional group multiregression models. Trunk flexion at ball release was a commonly shared predictor in the youth/high school (P = .04), high school/collegiate (P = .003), collegiate (P < .001), and the current study's professional group (P < .001). Youth, high school, collegiate, and professional pitchers had unique, predictive kinematic and anthropometric features predictive of pitch velocity. Leg length, stride length, trunk flexion at ball release, and maximal shoulder external rotation were predictive features that were shared between playing levels. Coaches, clinicians, scouts, and pitchers can consider both the unique and the shared predictive features at each playing level when attempting to maximize pitch velocity.

Influence of Lead Knee Extension on Ball Velocity and Elbow Varus Torque in Professional and High School Baseball Pitchers.

When the lead leg of a pitcher contacts the ground, the knee braces and then rapidly extends, initiating energy transfer to begin pelvis and trunk rotation. To investigate the relationship of lead knee extension during the pitching delivery with peak lead knee extension velocity, ball velocity, and elbow varus torque in high school and professional pitchers. Descriptive laboratory study. Data from 50 professional (PRO) and 50 high school (HS) pitcher groups were retrospectively analyzed. Pitchers threw 8 to 12 fastballs under 3-dimensional motion analysis (480 Hz). The groups were divided according to high or low lead knee extension: PRO-high (n = 18), PRO-low (n = 16), HS-high (n = 16), and HS-low (n = 17). Lead knee flexion, lead knee extension velocity, ball velocity, and elbow varus torque were analyzed between groups. Regression analyses were performed to quantify associations between lead knee extension and ball velocity and elbow varus torque for all pitchers. At foot contact, all pitchers landed with similar knee flexion. PRO-high and HS-high pitchers had significantly greater lead knee extension through remaining pitching time points compared with the PRO-low and HS-low pitchers. PRO-high pitchers had faster ball velocity than PRO-low pitchers (39.8 ± 1.1 vs 39.3 ± 1.3 m/s, respectively), and HS-high pitchers had faster ball velocity than HS-low pitchers (34.1 ± 2.6 vs 31.2 ± 1.8 m/s, respectively) (P < .05). PRO-high pitchers had decreased elbow varus torque compared with PRO-low pitchers (85.3 ± 10.7 vs 95.4 ± 13.3 N·m, respectively); conversely, HS-high pitchers had greater elbow varus torque than HS-low pitchers (64.2 ± 14.7 vs 56.3 ± 12.2 N·m, respectively). For every 1° increase in lead knee extension, ball velocity increased by 0.47 m/s (P < .001) and elbow varus torque increased by 0.27 N·m (P = .025). Proper lead knee extension allowed efficient energy transfer through the kinetic chain to produce optimal ball velocity and minimize elbow varus torque in professional pitchers. Conversely, while proper lead knee extension improved ball velocity among high school pitchers, this did not minimize elbow varus torque. Professional pitchers can extend their lead knee with minimal impact at the elbow. In high school pitchers, cognizance of proper full-body pitching mechanics remains a priority over increased velocity.

Comparison of the Effects of Compound Training, Plyometric Exercises, and Kettlebell Exercises on Strength, Power, Dynamic Balance, and Pitched Ball Velocity in 30 Male High School Baseball Pitchers Aged 16-19 Years.

BACKGROUND The purpose of this study was to determine how the combination of plyometric training (PT), which builds strength through fast, repetitive extensions and contractions, and kettlebell training (KT), using a device that is smaller than a barbell and allows for strength and full-body work, affects the physical performance and performance of high school pitchers during the season. MATERIAL AND METHODS Participants (n=30 males; age group=16-19 years) were randomized into 3 groups: compound training group (CTG) (n=10), plyometric training group (PTG) (n=10), and kettlebell group (KTG) (n=10). All groups performed training twice weekly for 4 weeks. Pre- and post-intervention assessments were conducted on isokinetic strength to measure strength, vertical jump (VJ) to measure power, dynamic balance (Y-balance), and ball speed (BS) to measure baseball performance. RESULTS We found there was increased strength, VJ, Y-balance, and BS in the CTG, PTG, and KTG (p=.000). CTG had significantly different results than PTG and KTG (p=.000). There was a significant difference in increased strength of the right knee joint flexors between PTG and KTG (p=.000). CONCLUSIONS CTG, PTG, and KTG for pitchers during the season improved significantly. These results suggest that combination training, rather than just 1 type of training, affects pitchers' strength, VJ, Y-balance, and BS during the season.

An Analysis of Intrapitch Variation in Joint and Segment Velocities With Throwing Arm Kinetics in High School and Professional Baseball Pitchers

Background: Improper sequencing order of maximal joint and segment velocities has been identified as an important predictor for both throwing arm kinetics and ball velocity. Purpose: To investigate the intrapitcher variation of maximal segment velocities and the relationship to throwing arm kinetics and ball velocity in high school (HS) and professional (PRO) pitchers. Study Design: Descriptive laboratory study. Methods: HS (n = 59) and PRO (n = 338) pitchers, instructed to throw 8 to 12 fastball pitches, were evaluated with 3-dimensional motion capture (480 Hz). Maximal joint and segment velocities were calculated for each pitch, and the standard deviation of the maxima was calculated per pitcher. These standard deviations were used to classify pitchers as “low variance” or “high variance” for each segmental velocity subgroup, “overall low variance” or “overall high variance” based on cumulative segment velocity variation, or “population,” with any pitcher eligible to be included in multiple subcategories. Maximal velocities and throwing arm kinetics were compared among the various subgroups. Results: The HS low-variance shoulder internal rotation velocity subgroup (4949 ± 642 deg/s) had significantly lower maximal shoulder internal rotation velocity compared with HS population (5774 ± 1057 deg/s) (P < .001); similar findings were observed for PROs (5269 ± 835 vs 5824 ± 1076 deg/s; P < .001), as well as lower shoulder superior force compared with the PRO population (14.8% ± 8.8% vs 17.8% ± 8.8% body weight; P = .001). The PRO low-variance lead knee extension velocity subgroup had significantly lower maximal lead knee extension velocity (216 ± 135 vs 258 ± 125 deg/s; P = .001) and shoulder distractive force (111.5% ± 14.4% vs 115.6% ± 15.9% body weight; P = .003) compared with the PRO population. The PRO overall low-variance subgroup had significantly lower shoulder distractive force (111.8% ± 14.1% vs 119.6% ± 15.5% body weight; P = .008) and elbow anterior force (40.6% ± 5.0% vs 43.6% ± 6.2% body weight; P = .008) compared with the PRO overall high-variance subgroup. Conclusion: HS and PRO pitchers with low variance for joint and segment velocities achieved significantly lower maximal velocities in the subgroup of interest, while preserving ball velocity. PRO pitchers with overall low variance among multiple maximal joint and segment velocities demonstrated decreased shoulder distractive and elbow anterior force. Clinical Relevance: PRO pitchers with low intrapitch variation in maximal joint and segment velocities may be viewed as kinetically conservative throwers. These pitchers with similarly maintained mechanics between pitches may have an increasingly regimented form that preserves kinetic forces about the throwing arm. The opposite may be true for PRO pitchers with increased variability in segmental velocities during their pitching motion, as they showed increased throwing arm kinetics including shoulder distractive and elbow anterior force compared with the overall low-variance group, theoretically increasing their risk of injury.

Workload Risk Factors for Pitching-Related Injuries in High School Baseball Pitchers

Background: Pitch counts are only one measure of the true workload of baseball pitchers. Newer research indicates that workload measurement and prevention of injury must include additional factors. Thus, current monitoring systems gauging pitcher workload may be considered inadequate. Purpose/Hypothesis: The purpose of this study was to develop a novel method to determine workload in baseball pitchers and improve processes for prevention of throwing-related injuries. It was hypothesized that our pitching workload model would better predict throwing-related injuries occurring throughout the baseball season than a standard pitch count model. Study Design: Cohort study; Level of evidence, 2. Methods: This prospective observational study was conducted at an academic medical center and community baseball fields during the 2019 to 2023 seasons. Pitchers aged 13 to 18 years were monitored for pitching-related injuries and workload (which included pitching velocity; intensity, using preseason and in-season velocity as a marker of effort; and pitch counts). Results: A total of 71 pitchers had 313 recorded pitcher outings, 11 pitching-related injuries, and 24,228 pitches thrown. Gameday pitch counts for all pitchers ranged from 19 to 219 (mean, 77.5 ± 41.0). Velocity ranged from 46.8 to 85.7 mph (mean, 71.3 ± 5.8 mph). Intensity ranged from 0.7 to 1.3 (mean, 1.0 ± 0.08). The mean workload was 74.7 ± 40.1 for all pitchers. Risk factors significant for injury included throwing at a higher velocity in game (P = .001), increased intensity (eg, an increase in mean velocity thrown from preseason to in-season; P < .001), and being an older pitcher (P = .014). No differences were found for workload between injured and noninjured pitchers because the analysis was underpowered. Conclusion: Our workload model indicated that throwing at a higher velocity, throwing at a higher intensity, and older age were risk factors for injury. Thus, this novel workload model should be considered as a means to identify pitchers who may be at greater risk for injury.

Return to Baseball Following an Anterior Shoulder Dislocation in a High School Baseball Pitcher: A Level 3 Case Report

A 17-year-old right-handed high school pitcher sustained a first-time anterior shoulder dislocation. The patient’s imaging revealed a small Hill–Sachs lesion; however, the clinical team’s decision was to manage it nonoperatively. In this case, the patient underwent 7 weeks of rehabilitation, which included general upper extremity strengthening exercises, a modified interval throwing program, and a pitching progression adapted specifically for the patient. After rehabilitation, the patient returned to live pitching with improvements in his pitching statistics. The uniqueness of this case is that it is a less common intervention approach posttreatment.

Weakening and factors of medial elbow dynamic stabilizers against elbow valgus laxity after repetitive pitching in high school baseball players

BackgroundOverhead throwing activity induces elbow valgus loading. Medial elbow dynamic stabilizers are thought important for medial elbow joint protection, but the effects of repetitive pitching on stabilizing function are largely unknown. This study aimed to investigate changes in the dynamic stabilizers during repetitive pitching as well as factors related to dynamic stabilizing ability. Our hypothesis was that repetitive pitching reduces dynamic stabilizer function, hence reducing the ability to minimize elbow valgus load. MethodsThirty high school baseball pitchers participated (age, 16.6 ± 0.5 years). Each participant pitched 100 times (5 blocks of 20 pitches). Prior to and after 100 pitches, medial elbow joint width and strain ratios, indicating the hardness of the ulnar collateral ligament (UCL) and forearm flexor-pronator muscles (FPMs), were measured using ultrasound at rest (non-contraction) and during gripping (contraction). Pre- and post-pitching data were compared using Paired t-tests. Multiple regression analysis was used to investigate factors related to the change rate in the medial elbow joint width during gripping. ResultsMedial elbow joint width during gripping significantly increased comparing pre- to post-pitching (P < 0.001). Both UCL and FPMs strain ratios after pitching significantly decreased (i.e., softer) compared to those before pitching (UCL, P = 0.001; FPMs, P = 0.006). The ratio of strain ratio in the UCL and FPMs (UCL/FPMs) during gripping prior to pitching was significantly and independently correlated with the change rate in medial elbow joint width during gripping (β = 0.44, P = 0.016). ConclusionPitching 100 balls induces a significant reduction in dynamic stabilizing ability against elbow valgus laxity. High school baseball pitchers should limit themselves to less than 100 pitches per game, or rest after 100 pitches before resuming. Furthermore, the ratio of hardness (UCL/FPMs) during dynamic stabilizing associated with gripping prior to pitching was significantly related to the change rate of elbow valgus laxity during the dynamic stabilization. Maintaining FPMs harder relative to UCL during gripping prevent elbow valgus laxity associated with repetitive pitching and may protect the medial elbow joint during repetitive pitching.

Factors Associated with Medial Elbow Torque Measured Using a Wearable Sensor in Junior High School Baseball Pitchers

There are no reports investigating the relationship between shoulder range of motion (ROM) and pitching elbow torque in junior high school pitchers. Therefore, we aimed to evaluate the factors associated with medial elbow torque in this population. Sixty-three junior high school baseball pitchers were recruited for this study. The participants completed a questionnaire and passive ROM measurements of shoulder abduction and horizontal adduction. All pitchers pitched three fastballs at maximum effort while wearing a wireless sensor recording pitching mechanics and elbow valgus torque for each pitch. Age (r = 0.65, p &lt; 0.001), height (r = 0.83, p &lt; 0.001), body weight (r = 0.82, p &lt; 0.001), BMI (r = 0.60, p &lt; 0.001), and ball velocity (r = 0.80, p &lt; 0.001) were significantly positively correlated with elbow valgus torque. Participants were divided into two groups based on elbow valgus torque, &gt;30 (high torque [HT]) and &lt;30 N·m (low torque [LT]). Age, height, body weight, BMI, and ball velocity were significantly higher in the HT group than in the LT group. The difference between dominant and non-dominant shoulder horizontal adduction ROM was 5.3 ± 9.3° and 1.0 ± 6.4° in the HT and LT groups, respectively, which was also significantly different. Ball velocity, age, larger physique, and increased restriction of the dominant shoulder’s horizontal adduction ROM were associated with higher medial elbow torque in junior high school pitchers. This suggests that improving the dominant shoulder’s horizontal adduction ROM contributes to preventing elbow injuries.

Pitching Restriction Policies in Adolescent and High-School Baseball Pitchers: Is It Time for an Updated Paradigm?

Pitching Restriction Policies in Adolescent and High-School Baseball Pitchers: Is It Time for an Updated Paradigm?

Characteristics Associated With Noncompliance of Current Pitch Smart Guidelines in High School Baseball Pitchers Throughout the United States.

Although pitch count and rest guidelines have been promoted for youth and adolescent baseball players for nearly 2 decades, compliance with guidelines remains poorly understood. The purpose of this study was to determine the frequency of compliance with Major League Baseball (MLB) Pitch Smart guidelines as well as the association between compliance and range of motion (ROM), strength, velocity, injury, and pitcher utilization. It was hypothesized that pitchers in violation of current recommendations would have increased strength, velocity, and injury. Case-control study; Level of evidence, 3. This was a prospective, multicenter study of 115 high school pitchers throughout the United States. Pitchers were surveyed about their compliance with current off-season, rest-related guidelines, and history of injury. During the preseason, pitchers underwent standardized physical examinations, and pitch velocity was measured. Pitch counts were collected during the baseball season that followed. Dynamometer strength testing of shoulder forward flexion, and external rotation as well as grip strength was recorded. We compared pitchers who were compliant with recommendations with those who were noncompliant using Student t and Mann-Whitney U tests. Based on preseason data, 84% of pitchers had violated current Pitch Smart guidelines. During the season, 14% had at least 1 violation of the Pitch Smart guidelines. Across both the preseason survey and in-season pitch counts, 89% of players had at least 1 violation of the Pitch Smart guidelines. While there were no significant differences in ROM or strength, the noncompliant group had higher maximum pitch velocity than the compliant group (74 ± 8 vs 69 ± 5 mph [119 ± 13 vs 111 ± 8 kph], respectively; P = .009). Players' self-reported velocity differed significantly from the direct measurement, for both peak velocity (80 ± 6 vs 73 ± 8 mph [129 ± 9 vs 117 ± 13 kph], respectively; P < .001) and mean velocity (73 ± 8 vs 53 ± 27 mph [117 ± 13 vs 85 ± 43 kph], respectively; P < .001). Most high school pitchers were not fully compliant with current Pitch Smart guidelines, and they tended to overestimate their peak velocity by 7 mph (11 kph). Pitchers who threw with greater velocity were at higher risk for violating Pitch Smart recommendations.

Poster 167: Increased Throwing Velocity is Correlated with a Higher Likelihood of Violating Current Pitch Count Recommendations in High School Baseball Pitchers.

Objectives: While pitch count and rest guidelines have been promoted for youth and adolescent baseball players for nearly two decades, compliance with guidelines remains poorly understood. The purpose of this study was to determine the frequency of compliance with Pitch Smart guidelines, as well as the association between compliance and range of motion, strength, velocity, injury, and pitcher utilization. Methods: This study was a prospective, multi-center study of high school pitchers, encompassing each region of the United States. Pre-season pitchers were surveyed about their compliance with current off- season rest-related guidelines and history of injury. Pre-season, pitchers underwent standardized physical examinations and pitch velocity was measured. During the high school season that followed, both pitch counts and injury incidence were collected. Results: One hundred and fifteen pitchers participated. Based upon pre-season data, 84% of pitchers had previously violated current pitch recommendation guidelines. During the season, 14% had at least one instance of a violation of the current pitch counts guidelines. Across both the pre-season survey and in-season pitch counts, 89% of players had at least one violation of the current Pitch Smart guidelines. While there were no significant differences in range of motion or strength, those pitchers who were non-compliant with guidelines in the pre-season had higher max pitch velocity (mean±standard deviation 74±8 miles per hour vs. 69±5 miles per hour, p=0.009). Pitchers self-reported their peak velocity at 7 MPH greater than the actual measured velocity. Only a single injury occurred during the season, precluding a comparison between groups. There were no significant differences in the incidence of a history of injury between those pitchers who were noncompliant with between-season rest guidelines (p=0.285). Conclusions: Most high school pitchers are non-compliant with current Pitch Smart guidelines, and they tend to overestimate their peak velocity by 7 MPH. Pitchers with greater velocity were at the highest risk for violating current pitch count recommendations. Since both increased throwing volume and pitch velocity are known risk factors for injury, these athletes may be at particular risk for subsequent injury. research is necessary to understand whether taking three consecutive month rest between seasons prevents pitching-related injury.

Poster 204: Changes in Elbow Stress and Ball Velocity During Reduced Effort Pitching: A Marker-Based Motion Capture Analysis

Objectives: 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 to maximum effort with respect to elbow stress and ball velocity. The purpose of this study is to determine whether elbow stress and ball velocity correlate with reduced effort pitching, whether elbow stress and ball velocity decrease proportionally while throwing at a reduced effort, and to assess intrathrower reliability. 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 marker-based 3D 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&lt;0.001 and p=0.003, respectively). However, the reductions in elbow stress and ball velocity were not proportional. At 75% effort throws, elbow stress decreased only 19% and ball velocity decreased only 10%. At 50% effort throws, elbow stress decreased only 25% and ball velocity decreased only 15%. Intrathrower reliability was excellent for elbow stress and ball velocity, with intraclass correlation coefficients all greater than or equal to 0.80. Conclusions: 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 of 13% and ball velocity decreased 8%. When baseball pitchers attempt to throw at a reduced effort of maximum, throwing metrics do not decrease proportionately. 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 sport. [Table: see text]

Comparison of Pitching Kinematics between Normal-Weight and Overweight Group in High School Baseball Pitchers

This study compared differences in pitching kinematics between normal-weight and overweight high school baseball pitchers. Twenty male pitchers were included in the study. According to the 2020 guidelines on the Body Mass Index (BMI) standard for children and adolescents by the Korean Society for the Study of Obesity, 10 participants with BMI below the 85% percentile were assigned to the normal-weight group, and 10 participants with BMI above the 85% percentile were assigned to the overweight group. The two groups threw 10 trials for a fastball with maximum effort. Out of 10 trials, three pitches thrown in the strike zone with the fastest velocity were extracted. The mean ball velocity was measured, and the mean and maximum angle and angular velocity of the knee, pelvis, trunk, shoulder, and elbow joints were calculated. The differences in the ball velocity, angle, and angular velocity between the two groups were compared using an independent t-test (p&lt;0.05). There were no differences in mean ball velocity between the two groups. However, compared with the normal-weight group, the overweight group showed smaller knee flexion, trunk forward tilt, trunk rotation, maximum trunk angular velocity, shoulder external rotation and maximum shoulder external rotation, while shoulder abduction and maximum elbow flexion were greater. These results suggest that the overweight group may have a high risk of soft tissue damage in the knee, shoulder, and elbow joints caused by limited movement of the trunk and inefficient movement between the extremities during power pitching.

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

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. 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. 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. 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.

고등학교 야구 투수의 전문 체력요인이 투구속도에 미치는 영향: 예비연구

This study was conducted to provide basic data for pitcher training and physical strength training by analyzing the effect of high school baseball pitcher’s professional fitness factors on throwing velocity. The subjects of the study were high school baseball pitchers(n=10) and evaluated using the Baseball Athletic Test(BAT). BAT was a field test for baseball pitchers and analyzed body composition, flexibility, muscular strength, leg power, agility, running speed, and throwing velocity, and the following results were derived. First, body composition(height, weight, body fat percentage, muscle mass) did not show a significant correlation with throwing velocity. Second, grip strength showed a significant correlation with pitching speed improvement(R²=.683, p＜.05) Third, vertical jump showed a significant correlation with throwing velocity(R²=.754, p＜.05). Fourth, 60yd sprint was found to have a statistically significant correlation with throwing velocity((R²=-.766, p＜.01). To summarize the above, baseball pitchers showed significant correlations with vertical jump, grip strength, and 60yd sprint. Therefore, leg power, grip strength, and running speed among professional physical fitness factors are judged to be important factors in improving pitcher’s throwing velocity, and are judged to be effective basic data for analyzing and training pitchers’ physical strength in the future.

Pitching Biomechanics and Shoulder Function in Baseball Pitchers with Scapular Dyskinesis.

The primary purpose was to investigate the influence of scapular dyskinesis (SD) on pitching biomechanics and shoulder function in high school baseball pitchers. The secondary purpose was to identify possible factors associated with shoulder function in pitchers with SD. Thirty-eight pitchers were classified into the SD group (n=26) or the non-SD group (n=12). They were evaluated with the Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) scale and clinical measurements of shoulder characteristics, and with measurements of scapular kinematics, muscle activation, and ball speed during fastball pitching. Compared to the controls, the pitchers with SD had less scapular external rotation (difference=11.3 degrees, ES=0.92, p=0.012) during overall pitching and less upper trapezius (UT) activation during the late cocking (difference=7.1%, ES=0.79, p=0.019) and acceleration phases (difference=12.5%, ES=0.75, p=0.035). Higher UT activation during the late cocking phase was significantly associated with higher KJOC scores (standardized β=0.415, p=0.039). In conclusion, deficits in scapular external rotation and decreased UT activation during pitching were found in pitchers with SD. Higher UT activation may be important for shoulder function in pitchers with SD.

Most high school baseball pitchers are using weighted ball throwing programs to increase ball velocity: crosssectional analysis of US high school pitchers

Weighted-ball velocity training programs are popular but may be associated with increased injury risk. The purpose of this study was to determine the current frequency of these programs, as well as their association with range of motion, strength, velocity, injury, and utilization in high school baseball pitchers. This was a multicenter, prospective, community-based study including high schools from the Northeastern, Southeastern, Midwestern, and Western regions of the United States. Preseason pitchers were surveyed about their use of weighted ball velocity programs and history of injury. Preseason pitchers underwent standardized physical examinations and pitch velocity was measured. During a single high school season, pitch counts and injury incidence were prospectively collected. In total, 115 pitchers were recruited, of whom 63% had participated in a weighted ball program. There were no differences in range of motion or strength between groups who used weighted balls and those who did not. Pitchers that utilized weighted ball programs demonstrated a higher average fastball velocity (114.26 vs. 106.22 km/h [71 vs. 66 mph]; P < .001) as well as peak fastball velocity (115.87 vs. 109.44 km/h [72 vs. 68 mph]; P= .001) compared to those that did not use weighted ball programs. Pitchers that utilized weighted ball programs were no more likely to be single-sport athletes (44%) than those who were multisport athletes (49%, P= .667). Within the group who had used a weighted ball program 29% (13/45) reported a history of injury and within the group who had not used a weighted ball program 25% (10/40) reported a history of injury (P= .687). As only a single injury occurred in the entire cohort, comparison of injury rates could not be completed. In this prospective study, the majority of high school pitchers reported using weighted ball programs to increase velocity, and these programs were associated with increased average and peak velocity compared to pitchers who did not use weighted ball programs. There were no significant differences in injury history between the 2 groups. Further study is necessary to understand the injury risk associated with weighted ball programs.

Range of motion patterning in trunk and upper and lower extremities of high school baseball pitchers

Range of motion patterning in trunk and upper and lower extremities of high school baseball pitchers

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.