High School Baseball Research Articles

Acceptable timing error at ball-bat impact for different pitches and its implications for baseball skills

In baseball hitting, batters need high precision timing control to hit the ball with bat’s sweet spot. Knowing the acceptable range of timing error for hitting the ball in the aimed direction for various pitch types is helpful to understand whether the cause of the batter's mis-hit is a spatial or temporal error and highlight the motor skills required by the batter. The purpose of this study was to determine the acceptable timing error in different baseball pitches and the impact characteristics of mis-hits. Twenty-six high school baseball players hit a ball launched from a pitching machine with three types of pitches: fastballs, curveballs, and slowballs. We recorded the three-dimensional behavior of the ball, bat, and human body (pelvis) using an optical motion capture system. We then defined the optimal impact location based on timing accuracy, and determined the acceptable range of timing error by the interactive relationship between the horizontal orientation of the bat’s long axis at the time of ball impact and the horizontal direction of the batted ball. The ±30° width in the horizontal direction of the batted ball was set as the precondition for the tolerance of timing. The acceptable timing error was ±7.9 ms for fastballs, ±10.7 ms for curveballs, and ±10.7 ms for slowballs, and the optimal timing for outside pitches was approximately 10 ms later than that for inside pitches. The timing error was also explained 38.1% by variation in the impact location along the long axis of the bat (R2 = 0.381, P < 0.001) and was minimized at a position close to the bat’s sweet spot. These results suggest that the optimal impact location and acceptable range of timing error depend on the pitching course and speed and that timing accuracy is essential to achieve the spatial accuracy required to hit the ball at the bat’s sweet spot.

Glenohumeral-Rotation-Deficits In High School, College, And Professional Baseball Pitchers With And Without An Mucl Injury

Glenohumeral-Rotation-Deficits In High School, College, And Professional Baseball Pitchers With And Without An Mucl Injury

Knee Pain - Baseball

HISTORY: A 16 year old high school hockey player and baseball pitcher noticed lateral knee pain and intermittent swelling for about 2 months prior to presentation. He does not recall any trauma or injury. He did have a viral URI and episode of strep pharyngitis several weeks before this started. He denies radiation of the pain. He does note some catching and locking sensation of the knee. He feels that his knee flexion is limited. He treated the knee with ice, ibuprofen, and acetaminophen through the season and was able to complete his baseball season prior to presenting to his PCP for evaluation. Because no definite etiology was identified in this visit, MRI was ordered, which showed complex loculated effusion, enlarged popliteal lymph nodes, and synovial thickening. There were no structural injuries appreciated. PHYSICAL EXAMINATION: Initial exam in the sports medicine clinic revealed tenderness at the lateral joint line and 1+ knee effusion. There was no erythema or warmth at the joint. He had full active and passive range of motion and full strength. Ligamentous testing was normal. DIFFERENTIAL DIAGNOSIS: PVNS Rheumatologic condition Lymphoma/Leukemia Lyme disease Traumatic hemarthrosis TEST AND RESULTS: Repeat MRI with additional views: Complex loculated effusion; Synovitis/synovial proliferation;No hemosiderin staining with blooming artifact Joint aspiration: 20 cc cloudy yellow synovial fluid; TNC 37,270, Neutrophils 73% Cytology: No malignant cells ANA: 1:80 homogeneous Rheumatoid Factor: Negative Lyme: Negative ESR: 9 CRP: 21.8 CBC: WBC 5.9, Hgb 15.5, Hct 45.4, Plt 287 FINAL WORKING DIAGNOSIS: Juvenile idiopathic arthritis (JIA) TREATMENT AND OUTCOMES: Referred to pediatric rheumatologist Bilateral knee aspiration and corticosteroid injection Prednisone taper Methotrexate therapy Check anti-CCP antibodies Referred to ophthalmology to rule out uveitis

BASEBALL PLAYERS DIAGNOSED WITH ULNAR COLLATERAL LIGAMENT TEARS DEMONSTRATE GREATER SIDE TO SIDE DIFFERENCES IN PASSIVE GLENOHUMERAL ABDUCTION RANGE OF MOTION COMPARED TO HEALTHY CONTROLS.

Numerous studies have shown that baseball players develop range of motion adaptations in their throwing arm. While some of these shoulder range of motion adaptations can lead to greater throwing velocity, excessive changes in shoulder range of motion can increase the risk of injury to the ulnar collateral ligament (UCL). The purpose of this study was to compare the passive GH-ABD ROM measures of baseball players with a diagnosed UCL tear (UCL group) to a group of age, activity, and position matched healthy controls (CONT group). The primary hypothesis was that baseball players with an UCL tear would have a greater loss of passive glenohumeral abduction range of motion in their throwing shoulder than healthy controls. A secondary hypothesis was that baseball players with an UCL tear would demonstrate similar glenohumeral abduction range of motion in their non-throwing arm and increased side-to-side glenohumeral abduction differences compared to the healthy cohort. Retrospective prospective case-control study. The UCL group had significantly greater glenohumeral abduction range of motion on their throwing shoulder (132.5 °±8.3 °) than the CONT group (120.19 °±11.2 °, p = 0.000). Similarly, the UCL group had increased glenohumeral abduction range of motion on their non-throwing shoulder (141.2 °±9.5 °) compared to the CONT group (124.1 °±11.4 °, p = 0.000). Additionally, the UCL group had a greater glenohumeral abduction difference (-8.7 °±8.4 °) than the CONT group (-3.8 °±7.7 °, p = 0.001). In contrast to the original hypotheses, high school and collegiate baseball players that sustained an UCL injury presented with greater glenohumeral abduction range of motion in both their throwing and non-throwing shoulders compared to healthy controls. However, the finding of greater side-to-side glenohumeral abduction range of motion deficits in the UCL group when compared to the matched healthy controls confirms the secondary hypothesis. Level 3.

Baseball Pitchers’ Perceived Effort Does Not Match Actual Measured Effort During a Structured Long-Toss Throwing Program

Background: During rehabilitation throwing programs, baseball players are commonly asked to throw at reduced levels of effort (ie, 50% effort, 75% effort, etc) to moderate stress to healing tissues. It is currently unknown how changes in players’ perceived exertion compares with changes in actual exertion during structured long-toss programs. Purpose: To determine whether decreased effort correlates with decreased throwing metrics, whether metrics decrease proportionally with reductions in perceived effort, and to quantify intrathrower variability. Study Design: Descriptive laboratory study. Methods: Sixty male high school and collegiate baseball pitchers participated in a structured throwing program. A motusBASEBALL sleeve was worn by all players, which measured elbow varus torque, arm velocity, arm slot, and shoulder rotation. Ball velocity was measured with a radar gun. Each pitcher threw 5 throws a distance of 120 ft with 3 efforts: maximum effort, 75% effort, and 50% effort. Throwing metrics were compared among the 3 levels of effort to see if each 25% decrease resulted in proportional decreases in elbow varus torque and ball velocity. Intrathrower variability was determined for each throwing metric at each degree of effort. Results: All throwing metrics decreased as players decreased their perceived effort (P < .001). However, these observed decreases were much smaller in magnitude than the decreases in perceived effort. During the 75% effort throws, elbow varus torque was only reduced to 93% of maximum and velocity dropped to 86% of maximum. Similarly, for the 50% effort throws, elbow varus torque remained 87% of max effort torque, while velocity remained 78% of max. Intrathrower reliability was considered excellent for most metrics (intraclass correlation coefficient, >0.75). Conclusion: For every 25% decrease in perceived effort, elbow varus torque only decreased 7% and velocity only decreased 11%. Thus, when players throw at what they perceive to be reduced effort, their actual throwing metrics do not decrease at the same rate as their perceived exertion. Clinical Relevance: Measured effort decreased with decreasing perceived effort, but these were not proportional. This has significant implications for physical therapists, physicians, trainers, coaches, and athletes to understand and monitor elbow stress during the rehabilitation process.

Change in MRI findings of medial collateral ligament injury in adolescent baseball players with no clinical symptoms over time

Elbow screening of adolescent baseball players began in 2014 using ultrasound, palpation, and dedicated magnetic resonance imaging (MRI). We frequently encountered subjects showing MCL injury on MRI but no clinical symptoms. We assessed variations in asymptomatic MCL injury findings at follow-up MRI, and clarified the pathogenesis of these findings. Using a 0.2-T-dedicated MRI, 30 subjects with asymptomatic MCL injury at initial MRI who agreed to follow-up MRI were included. We classified the findings at repeat MRI as follows: (a) disappeared, (b) better, and (c) worse. There were 6, 16, and 8 subjects in groups a, b, and c, respectively. The average age at follow-up was 14.0, 12.1, and 12.4years in groups a, b, and c, respectively. There were significant differences between groups a and b and between groups a and c. Average height at follow-up of groups a, b, and c was 1.64, 1.52, and 1.57cm, respectively, with a statistically significant difference between groups a and b. The average size of the short axis of the MCL of subjects in group a was 2.0cm on the dominant side and 1.5cm on the contradominant side (P < 0.04). Players with asymptomatic MCL injury can continue to play baseball with no limitations, as these findings usually disappear around the age of 14.0years, when the growth spurt occurs. This finding may be a precursor of 'adaptation', which is generally observed in high school baseball players, suggesting that the MCL adapts as growth occurs.

Posterior Labral Repairs of the Shoulder Among Baseball Players: Results and Outcomes With Minimum 2-Year Follow-up

Background: There is a paucity of information regarding the treatment of posterior labral tears of the shoulder for baseball players. Reports regarding treatment and postoperative outcomes are more limited than its anterior and superior counterparts. Purpose: To evaluate the clinical presentation, surgical findings, postoperative outcomes, and rate of return to sport after arthroscopic repair of posterior labral injuries of the shoulder among baseball players. Study Design: Case series; Level of evidence, 4. Methods: Retrospective review was performed of baseball players who underwent arthroscopic posterior labral repair between 2009 and 2015 by a single surgeon, with a minimum 2-year follow-up. The group was composed of 32 male patients involved in recreational (6.3%), high school (43.8%), college (31.3%), and professional (18.8%) baseball, with a mean age of 20.5 years. Patients were categorized by chief complaint, clinical findings, surgical findings, and concomitant procedures performed. Pre- and postoperative measures included pain scale, range of motion, American Shoulder and Elbow Surgeons shoulder score, return to play, and patient satisfaction. Results: A variety of tear patterns were identified; 32% involved 90° of the posterior superior labrum; 35% involved the posterior 180°; and 32% involved 90° of the posterior inferior labrum. The dominant mechanism of injury was throwing (34.4%). The most common chief complaint was pain (n = 25, 78%), followed by pain and instability symptoms (n = 6, 18.8%), with only 3% citing isolated sensation of instability. Magnetic resonance imaging clearly identified tear patterns in 75% of cases. American Shoulder and Elbow Surgeons scores significantly improved (P < .0001), increasing on average 30.9 points from the preoperative mean of 65.4 to a postoperative mean of 96.3. No significant range of motion deficits were noted. Tear size and number of anchors utilized did not influence outcomes. Ninety-four percent of athletes returned to play, 61% at previous levels, and 6% did not return. Pitchers had a lower return to previous level of play than position players (41% vs 86%, P = .0113). Conclusion: Arthroscopic treatment of posterior labral tears of baseball players was effective in improving pain and function, resulting in 94% patient satisfaction and 94% return to sport, with 61% returning to previous level of play. Patient presentation is variable, with a majority of patients citing pain rather than instability.

Current Workload Recommendations in Baseball Pitchers: A Systematic Review

Background: Several recommendations have been made regarding pitch counts and workload for baseball players of different levels, including Little League, high school, collegiate, and professional baseball. However, little consensus is found in the literature regarding the scientific basis for many of these recommendations. Purpose: The primary purpose of this study was to summarize the evidence regarding immediate and long-term musculoskeletal responses to increasing pitching workload in baseball pitchers of all levels. A secondary purpose of this review was to evaluate the extent to which workload influences injury and/or performance in baseball pitchers. Study Design: Systematic review. Methods: We performed a systematic search in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies addressing physiologic and/or pathologic musculoskeletal changes in response to a quantifiable pitching workload. We included studies examining the effects of pitching workload on performance, injury rate, and musculoskeletal changes in Little League, high school, collegiate, and professional baseball players. Results: We identified 28 studies that met our inclusion and exclusion criteria: 16 studies regarding Little League and high school pitchers and 12 studies regarding collegiate and professional pitchers. The current evidence presented suggests that increased pitching workload may be associated with an increased risk of pain, injury, and arm fatigue in Little League and high school pitchers. However, little consensus was found in the literature regarding the association between pitching workload and physiologic or pathologic changes in collegiate and professional pitchers. Conclusion: Evidence, although limited, suggests the use of pitch counts to decrease injury rates and pain in Little League and high school baseball pitchers. However, further research must be performed to determine the appropriate number of pitches (or throws) for players of different ages. This systematic review reported conflicting evidence regarding the use of pitch counts in college and professional baseball. Future high-quality research is required to determine the role, if any, of pitch counts for collegiate and professional pitchers.

Differential Diagnosis: Orthopedic Injury or Oncologic Process—A Case Report

Background and Purpose: Patients referred for orthopedic management of musculoskeletal conditions warrant careful consideration when linear progress or decline is observed. Case Description: A 17-year-old male high school baseball player was referred by an orthopedic surgeon with a diagnosis of right medial epicondylitis. Physical therapy history, examination, and differential diagnosis led to “red flag” identification and a referral back to the orthopedic surgeon for diagnostic imaging. After negative findings, the patient returned for continued treatment of right medial epicondylitis. Upon a second physical therapy evaluation, symptoms progressed and functional capabilities decreased. This prompted the physical therapist to refer the patient and his family for additional medical examination. Outcomes: Review of previous diagnostic imaging led to the diagnosis of a primary osteoblastoma, surgical intervention, and physical therapy, with a quick return to independent functioning. Within 4 months, the aggressive tumor returned, which prompted referral to an orthopedic tumor specialist, and the patient underwent a second more extensive surgery and within a year, a third, most aggressive surgical procedure. He continues to receive medical and physical therapy follow-up visits and has not returned to competitive sports. Discussion/Conclusion: Physical therapists consistently demonstrate the ability to be extremely competent, efficient, and cost-effective in managing neuromusculoskeletal dysfunction. It is imperative to recognize signs, symptoms, and “red flags,” which indicate pathological conditions outside the scope of physical therapy practice, and ensure prompt and appropriate referrals.

Use of an Elbow Brace During Repetitive Pitching Does Not Cause an Increased Mechanical Burden on the Throwing Arm.

Repetitive pitching induces an increase in medial elbow joint space gapping and may consequently lead to local tissue stress and injury. Use of an elbow brace may prevent this from occurring by preventing an increase of medial elbow joint space gapping. However, an elbow brace adds weight to the limb and may increase the burden on the throwing arm. To investigate whether use of an elbow brace during repetitive pitching reduces shoulder and arm range of motion and grip strength. Prospective crossover study. University campus. Twenty-five healthy high school baseball players. Each participant pitched 100 times under two conditions: without an elbow brace (control) and wearing an elbow brace. Shoulder and elbow range of motion (ROM) before pitching and after every block of 20 pitches. Grip strength before pitching and after 100 pitches. There was no significant main effect and interaction for ROM between the two conditions and between pitching sets. In both conditions, grip strength after 100 pitches was significantly lower than that before pitching (P < .05). When the two conditions were compared, there was no significant difference before pitching or after 100 pitches. Use of elbow brace does not alter shoulder and elbow ROM or decrease grip strength after repetitive pitching up to 100 times compared with a no brace condition. An elbow brace can be used during repetitive pitching without causing an increased mechanical burden on the throwing arm. II.

Association of Functional Movement Screen and Y-Balance Test Scores With Injury in High School Athletes.

Lisman, P, Hildebrand, E, Nadelen, M, and Leppert, K. Association of functional movement screen and Y-Balance Test scores with injury in high school athletes. J Strength Cond Res 35(7): 1930-1938, 2021-The purpose of this study was to determine the association between functional movement screen (FMS) and Y-Balance Test (YBT) performance and lower extremity injury in a sample of male high school athletes. A total of 124 high school football (n = 89), lacrosse (n = 25), and baseball (n = 10) players underwent FMS and YBT before the start of their competitive seasons. Time loss lower extremity injury incidence data were tracked by each team's certified athletic trainer and used for analysis. Receiver operating characteristic (ROC) curves were calculated to determine the optimal cutpoints for FMS composite score (CS) and YBT measures, including CS and reach distance asymmetry for anterior, posteromedial, and posterolateral directions, for predicting injury. No cutpoints on the ROC curves maximized sensitivity and specificity; therefore, FMS CS and YBT measures (CS and asymmetry) were analyzed as continuous variables. Logistic regression models adjusted for age and sport revealed no significant associations between FMS CS and lower extremity injury (odds ratio [OR] = 0.99; 95% confidence interval [CI] = 0.83-1.20). Similar findings were found for YBT asymmetry in all directions (ORs ranged from 0.98 to 1.08) and CS (OR = 0.99; 95% CI = 0.95-1.04). There were also no significant associations between the presence of asymmetry and low score (score of 1) on any individual FMS test and injury. Overall, FMS and YBT were not associated with increased risk of lower extremity injury in this sample of high school athletes. These findings do not support the use of FMS and YBT as stand-alone injury risk assessments in high school athletes.

고등학교 학생야구선수의 학업성취 수준 및 정의적 특성 분석

The purpose of this study was to explore the different academic achievement levels and different affective characteristics of high school baseball players. 52 high school baseball players were selected from high school “A” in city “S” for this study. Researcher used the program called iNAEA which is provided from KICE (Korea Institute of Curriculum & Evaluation) to create different levels of elementary and junior high schools’ test reports in Korean, English and Mathematics subjects; The level of academic achievement and definitive characteristics of baseball players students’ were measured based on the research and questionnaires on the affective characteristics in national level. The study results and comparison showed that the levels of academic achievement of high school baseball players were following: low junior high school students (grade7) in Korean subject, high elementary school students (grade 4 to grade 6) in Mathematics, and between low and high junior high school (grade 7 to 9) in English. In addition, there was no relationship found among academic achievement, students’ backgrounds and affective characteristics of students; yet there was relationship between school happiness and other affective characteristics was confirmed.

국내 고교야구선수들의 상대연령효과(RAE)분석

국내 고교야구선수들의 상대연령효과(RAE)분석

Glenohumeral rotation deficits in high school, college, and professional baseball pitchers with and without a medial ulnar collateral ligament injury

It is unclear how a glenohumeral internal rotation (IR) loss (GIRLoss), a glenohumeral external rotation (ER) gain (GERGain), or a total rotational motion (TRM) deficit (TRMD) predict medial ulnar collateral ligament (MUCL) injury risk among high school (HS), college (COLL), and professional (PRO) baseball pitchers with and without MUCL injury. We hypothesized that pitchers with MUCL injury would have more GIRLoss and TRMD compared with pitchers without MUCL injury, with no differences in IR, ER, TRM, GIRLoss, GERGain, and TRMD. The study equally divided 216 male HS, COLL, and PRO pitchers into the MUCL injury group (n = 108) and a control group (n = 108) without MUCL injury. The control group was matched with the MUCL injury group according to number, level of play, and age. Bilateral shoulder passive IR/ER was measured and GIRLoss, GERGain, TRM, and TRMD calculated. A 2-way analysis of variance (P < .05) was used to assess shoulder rotational differences among the 2 groups and 3 pitching levels. Compared with the control group, the MUCL injured group had more GIRLoss (21° ± 14° vs. 13° ± 8°; P < .001), GERGain (14° ± 9° vs. 10° ± 9°; P = .004), and TRMD (7° ± 13° vs. 3° ± 9°; P = .008). For all pitching levels, approximately 60% of pitchers in MUCL injury group had GIRLoss >18° compared with approximately 30% of those in the control group. Approximately 60% of pitchers in the MUCL injury group had TRMD >5° compared with 50% of pitchers in the control group. No differences were observed among HS, COLL, and PRO pitchers for GIRLoss (16° ± 12°, 17° ± 11°, 19° ± 13°, respectively; P = .131), GERGain (11° ± 9°, 11° ± 10°, 13° ± 10°, respectively; P = .171), TRMD (5° ± 11°, 6° ± 11°, 5° ± 14°, respectively; P = .711), and throwing shoulder ER (111° ± 10°, 111° ± 11°, 113° ± 9°, respectively; P = .427), IR (50° ± 11°, 49° ± 11°, 48° ± 10°, respectively; P = .121), and TRM (162° ± 14°, 160° ± 15°, 161° ± 14°, respectively; P = .770). Greater GIRLoss, GERGain, and TRMD in MUCL injured pitchers compared with uninjured pitchers implies these variables may be related to increased MUCL injury risk, especially because GIRLoss >18° and TRMD >5° demonstrate an increased MUCL injury risk. Shoulder rotational motion and deficits do not vary among HS, COLL, and PRO levels of pitchers.

Segmental Power Analysis of Sequential Body Motion and Elbow Valgus Loading During Baseball Pitching: Comparison Between Professional and High School Baseball Players.

Background:Pitching-related elbow injuries remain prevalent across all levels of baseball. Elbow valgus torque has been identified as a modifiable risk factor of injuries to the ulnar collateral ligament in skeletally mature pitchers.Purpose:To examine how segmental energy flow (power) influences elbow valgus torque and ball speed in professional versus high school baseball pitchers.Study Design:Descriptive laboratory study.Methods:A total of 16 professional pitchers (mean age, 21.9 ± 3.6 years) and 15 high school pitchers (mean age, 15.5 ± 1.1 years) participated in marker-based motion analysis of baseball pitching. Ball speed, maximum elbow valgus torque (MEV), temporal parameters, and mechanical power of the trunk, upper arm, and forearm were collected and compared using parametric statistical methods.Results:Professional pitchers threw with a higher ball speed (36.3 ± 2.9 m/s) compared with high school pitchers (30.4 ± 3.5 m/s) (P = .001), and MEV was greater in professional pitchers (71.3 ± 20.0 N·m) than in high school pitchers (50.7 ± 14.6 N·m) (P = .003). No significant difference in normalized MEV was found between groups (P = .497). Trunk rotation time, trunk power, and upper arm power combined to predict MEV (r = 0.823, P < .001), while trunk rotation time and trunk power were the only predictors of ball speed (r = 0.731, P < .001). There were significant differences between the professional and high school groups in the timing of maximum pelvis rotation velocity (42.9 ± 9.7% of the pitching cycle [%PC] vs 27.9 ± 23.4 %PC, respectively; P < .025), maximum trunk rotation (33 ± 16 %PC vs 2 ± 23 %PC, respectively; P = .001), and maximum shoulder internal rotation velocity (102.4 ± 8.9 %PC vs 93.0 ± 11.7 %PC, respectively; P = .017).Conclusion:The power of trunk motion plays a critical role in the development of elbow valgus torque and ball speed. Professional and high school pitchers do not differ in elbow torque relative to their respective size but appear to adopt different patterns of segmental motion.Clinical Relevance:Because trunk rotation supplies the power associated with MEV and ball speed, training methods aimed at core stabilization and flexibility may benefit professional and high school pitchers in reducing the injury risk and improving pitching performance.

Risk Factors for Baseball-Related Arm Injuries: A Systematic Review.

Background:Contributing factors for arm injuries among baseball players have been described. However, no review has systematically identified risk factors with findings from prospective cohort studies.Purpose:To systematically review prospective cohort studies that investigated risk factors for arm injury among baseball players.Study Design:Systematic review; Level of evidence, 3.Methods:Electronic databases were searched for relevant English-language studies. Titles, abstracts, and full-text articles were screened by 2 blinded reviewers to identify only prospective cohort studies and randomized controlled trials. Two independent investigators screened each article for appropriate criteria.Results:Fourteen prospective articles were selected for this review. Youth, high school, and professional baseball players (N = 2426) were pooled, and 43 risk factors were assessed in relation to general arm, shoulder, and elbow injuries. All studies evaluated players for at least 1 season. Deficits in preseason shoulder range of motion and strength were significant risk factors for general arm or shoulder injury among high school and professional players. Elbow and shoulder varus torque at peak external shoulder rotation during pitching, high pitch velocity, and shoulder rotational and flexion deficits were risk factors for elbow injuries among professional pitchers. Pitching >100 innings in 1 year, being aged 9 to 11 years, being a pitcher or catcher, training >16 hours per week, and having a history of elbow pain were significant risk factors for elbow injury among youth players.Conclusion:History of elbow pain and age had a high risk of associated elbow injury among youth players. Training or pitching load also increased elbow injury risk for youth athletes. Loss of shoulder range of motion appears to increase risk for elbow injury among professional athletes. Single time-point data collections per season, studies with the same sample population, and studies with self-reported injury and risk factor data may limit the interpretation of these findings. Health care professionals should use caution when assessing injury risk during evaluation and making decisions about the training workload and playing time of baseball players.

The First Decade of Web-Based Sports Injury Surveillance: Descriptive Epidemiology of Injuries in US High School Boys' Baseball (2005-2006 Through 2013-2014) and National Collegiate Athletic Association Men's Baseball (2004-2005 Through 2013-2014).

The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of boys' and men's baseball injury data. To describe the epidemiology of injuries sustained in high school boys' baseball in the 2005-2006 through 2013-2014 academic years and collegiate men's baseball in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance. Descriptive epidemiology study. Online injury surveillance from baseball teams in high school boys (annual average = 100) and collegiate men (annual average = 34). Boys' or men's baseball players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college, respectively. Athletic trainers collected time-loss injury and exposure data. Injury rates per 1000 athlete-exposures (AEs) were calculated. Injury rate ratios (IRRs) with 95% confidence intervals (CIs) compared injury rates by school size or division, time in season, event type, and competition level. The High School Reporting Information Online system documented 1537 time-loss injuries during 1 573 257 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2574 time-loss injuries during 804 737 AEs. The injury rate was higher in college than in high school (3.20 versus 0.98/1000 AEs; IRR = 3.27; 95% CI = 3.07, 3.49). The competition injury rate was higher than the practice injury rate in high school (IRR = 2.27; 95% CI = 2.05, 2.51) and college (IRR = 2.32; 95% CI = 2.15, 2.51). Baseball players at the high school and collegiate levels sustained a variety of injuries across the body, with the most common injuries reported to the upper extremity. Many injuries also occurred while fielding or pitching. Injury rates were greater in collegiate versus high school baseball and in competition versus practice. These findings highlight the need for injury-prevention interventions focused on reducing the incidence of upper extremity injuries and protecting batters from pitches and fielders from batted balls.

高校野球におけるスポーツ傷害発生の実態調査—Non-Time-Loss傷害に着目して—

高校野球におけるスポーツ傷害発生の実態調査—Non-Time-Loss傷害に着目して—

Shoulder and elbow pain in junior high school baseball players: Results of a nationwide survey

BackgroundDespite proposals and guidelines to prevent baseball injuries in young players by societies and organizations, many shoulder and elbow injuries continue to occur among junior high school baseball players. In order to investigate the training conditions of junior high school baseball players and the risk factors for shoulder and elbow pain in the players, we conducted a questionnaire survey among junior high school baseball players throughout the country. MethodsThe questionnaire survey was conducted among junior high school baseball players in September 2016. ResultsA total of 11,134 junior high school baseball players belonging to 495 teams responded to the survey. Among these, 4004 players trained every day of the week and 1151 players played baseball games every month with no off-season. Among 9752 players who did not have shoulder and/or elbow pain in the spring and summer of 2015, 19.2% of players experienced elbow pain over the course of one year, 13.6% of players experienced shoulder pain, and 28.0% complained of shoulder and/or elbow pain. The frequency of elbow pain was more than that of shoulder pain. At risk for shoulder pain were pitchers and catchers and second-year students, while risk factors for elbow pain were playing pitcher and catcher positions, pitching or throwing ≥300 balls per week, playing ≥10 games on average per month and being left-handed. ConclusionRisk factors for shoulder pain were different from those for elbow pain. To prevent elbow pain, coaches should pay attention to pitchers and catchers and left-handed players and not allow players to pitch or throw ≥300 full-power balls per week or participate in ≥10 games per month. They should also pay attention to pitchers and catchers and second-year students to prevent shoulder pain. It is important for coaches to train multiple pitchers and catchers.

Relationship between the elbow joint valgus instability and forearm flexor muscle strength in high school pitchers with and without symptom.

Earlier reports describe forearm flexor muscles as active stabilizers of the elbow to valgus stress during throwing motion. Given high school pitchers' history of elbow symptoms, this study assesses its relation to elbow valgus joint instability and forearm flexor muscle strength. Ultrasound examination was made for 132 high school baseball pitchers with and without valgus stress of the medial aspect of the bilateral elbows. They had completed a self-administered questionnaire related to self-satisfaction score (0-100) for pitching performance and throwing-related elbow joint pain sustained during the prior year. Using a digital manual muscle strength meter, we examined the grip strength and muscle strength of the flexor carpi ulnaris (FCU). For participants with and without a history of elbow symptom, we compared differences of ulnohumeral joint space width with and without valgus stress and grip and FCU muscle strength. For ulnohumeral joint width difference with and without valgus stress, pitchers with an elbow symptom and those without elbow symptom history on the throwing side were not significantly different. No difference was found in the grip strength or FCU muscle strength of the throwing side for each group. Positive significant association was found between FCU muscle strength on the pitching side and the self-evaluation score for pitching performance ( r = 0.27, p = 0.002). However, no association was found between the elbow valgus instability and the forearm flexor muscle strength. FCU muscle strength might influence high school baseball pitching performance.