High School Baseball Players Research Articles

The relationship between scapular position and glenohumeral rotational range of motion in high school baseball players.

Past research indicated that scapular malposition is related to the glenohumeral internal rotation deficit (GIRD). However, there is no research examining the effect of throwing-related pain on this relationship. This study investigated the relationship between scapular position and range of motion (ROM) and compared the difference in this relationship between with and without throwing-related pain. Forty male baseball players in high school were recruited for this study. The existence and degree of throwing-related pain were obtained from a questionnaire. Participants were divided into 2 groups according to the presence or absence of the pain. Glenohumeral internal and external rotation ROM (abduction internal rotation angle and abduction external rotation angle [ABER], respectively) were measured using a digital inclinometer. The pectoralis minor muscle length was measured using a vernier caliper and scapula index, which indicated the scapular position, measured using a measuring tape. All these measurements were taken on both dominant and nondominant sides. The GIRD and total motion arc (TMA) deficit were calculated from the ROM measurements. Groups were compared using a mixed-model analysis of variance. There was a significant interaction between group and ABER dominance. Other variables were not seen as the interaction effect. There was a significant positive correlation between the scapula index and TMA (r=0.47, P=.02) and a negative correlation between the scapula index and GIRD (r=-0.65, P<.01) in the dominant side of the pain group. In addition, in the nondominant side of the pain group, the scapula index and ABER were significantly correlated (r=0.43, P=.04). The results of this study indicate that the scapular position is associated with the glenohumeral ROM in high school baseball players. In addition, this study demonstrated that the scapular internally rotated position was correlated with the GIRD and TMA deficit in high school baseball players who had throwing-related pain. On the other hand, the scapular externally rotated position was correlated with increased ABER, mainly in the pain-free baseball players or on the nondominant side. These results indicated that the scapular position might affect the glenohumeral rotational ROM in high school baseball players.

Comparison of elbow valgus laxity and medial elbow stabilizer parameters during repetitive pitching between high school baseball players with and without a history of medial elbow injury.

Adolescent baseball players with a history of medial elbow injury are often reinjured during demanding practice sessions or games. The physical characteristics of baseball players with a history of medial elbow injury have been reported in several previous studies, but the nature of their medial elbow stabilizers is unknown. This study investigated the difference in characteristics of elbow valgus laxity and medial elbow stabilizer parameters between baseball players with and without a history of medial elbow injury, prior to and during repetitive pitching. Sixteen high school baseball players with no history of medial elbow injury (No-Injury group) and 14 high school baseball players with a history of medial elbow injury (Injury History group) participated. The participants pitched 100 fastballs. Medial elbow joint-space gapping and strain ratio indicating tissue elasticity of ulnar collateral ligament (UCL) and forearm flexor-pronator muscles (FPMs) were measured by ultrasound before pitching and following each of five 20-pitch blocks. Student t tests and Mann-Whitney U tests were used to compare each parameter between groups. Medial elbow joint-space gapping and UCL elasticity were not significantly different between the 2 groups in each pitching block (P>.05). The strain ratio of FPMs before pitching and after 100 pitches in the Injury History group were significantly greater than that in the No-Injury group (No-Injury vs. Injury History group: before pitching, 0.47±0.19 vs. 0.68±0.26, P=.016; 100 pitches, 0.35±0.12 vs. 0.53±0.20, P=.007). In the other pitching blocks, there was no significant difference between groups, but the effect size was medium and showed a similar tendency (20 pitches, P=.069, Cohen d=0.69; 40 pitches, P=.116, Cohen d=0.59; 60 pitches, P=.102, Cohen d=0.62; 80 pitches, P=.058, Cohen d=0.72). The results of this study indicate that FPM elasticity at baseline and during repetitive pitching in players with a history of medial elbow injury was harder than in players without injury history. This may suggest that baseball players with a history of medial elbow injury increase support of their previously injured medial elbow by hardening FPM elasticity to counteract elbow valgus stress generated during pitching, which may lead to long-term change in the FPMs. Therefore, physical management for this change may be important to prevent reinjury in baseball players with a history of medial elbow injury.

Efficacy of Injury Prevention Using Functional Movement Screen Training in High-School Baseball Players: Secondary Outcomes of a Randomized Controlled Trial.

This study of a randomized controlled trial aimed to clarify the effect of functional movement screen (FMS) training on the FMS score and the number of injuries in high-school baseball players. Accordingly, 71 high-school baseball players (age: 15-17 years) were randomized into an intervention group (n = 37; FMS training 4 times per week for 12 weeks on the ground of each team) or a control group (n = 34; team practice without limits). No significant differences were observed in terms of the participant characteristics of the two groups. The FMS score of the intervention group significantly increased after 12 weeks of training compared with the control group. However, there was no difference between the groups in terms of the FMS score after 24 weeks. Injuries in the intervention group were significantly reduced after 24 weeks. The time lost due to noncontact injuries (12 weeks/follow-up) was 56.5 h/113 h in the intervention group and 33 h/325.5 h in the control group. Injuries were found all over the body. Based on these results, FMS training was proven to reduce injury in high-school baseball players. Although continued training is required to improve FMS scores, the number of injuries decreased after training.

Clinical characteristics of early-stage lumbar spondylolysis detected by magnetic resonance imaging in male adolescent baseball players

BackgroundMany adolescent athletes experience low back pain; the most common cause is lumbar spondylolysis. Although early identification of lumbar spondylolysis in adolescent athletes is critical, few studies have focused on identifying the early stages of spondylolysis in baseball players. This study aimed to investigate the clinical characteristics of early-stage spondylolysis in male adolescent baseball players. MethodsThe participants comprised male junior and high school baseball players. Before magnetic resonance imaging, we recorded their demographic data, low back pain characteristics, and physical findings (lumbar flexion, extension, Kemp's test and the provocative tenderness of a spinous process). After the imaging evaluation, the association among low back pain characteristics, physical findings and the final diagnosis (early-stage spondylolysis or not) were investigated using univariate and multivariable analyses. ResultsA total of 171 players were included in this study. Univariate analyses indicated that the characteristics associated with early-stage spondylolysis were longer duration of low back pain (P = 0.0085), low back pain-related interference while running (P = 0.0022), low back pain starting with laterality (P = 0.0001), lumbar extension (P = 0.022), positive Kemp's test (P = 0.020), and the tenderness of a spinous process (P = 0.0003). After adjusting for confounding factors (age and position), we found that early-stage spondylolysis was significantly associated with low back pain duration ≥4 weeks (odds ratio 3.13, 95% confidence interval 1.42–6.92; P = 0.0048), low back pain-related interference while running (odds ratio 2.89, 95% confidence interval 1.30–6.46; P = 0.0094), low back pain starting with laterality (odds ratio 2.78, 95% confidence interval 1.24–6.27; P = 0.0133), and the tenderness of a spinous process (odds ratio 3.00, 95% confidence interval 1.36–6.57; P = 0.0062). ConclusionsMale adolescent baseball players with early-stage spondylolysis might have low back pain duration of more than four weeks, low back pain-related interference while running, and a history of low back pain starting with laterality. The tenderness of a spinous process might be helpful in the diagnosis of early-stage spondylolysis in male adolescent baseball players.

A Field-expedient Arm Care Screening Tool Can Identify Musculoskeletal Risk Factors in Baseball Players.

Preseason movement screening can identify modifiable risk factors, deterioration of function, and potential for injury in baseball players. Limited resources and time prevent high school baseball coaches from performing movement screens on their players. The arm care screen (ACS) will be highly sensitive to detecting musculoskeletal risk factors. Cross-sectional. Level 3. A total of 150 baseball players were independently scored on the ACS electronically by reviewing a video recording of each player's screening performance. Discriminability of the ACS was determined with a 2 × 2 contingency table dichotomizing musculoskeletal risk factors as present or absent based on a predetermined cutoff value and those who passed or failed the corresponding ACS subtest. High sensitivity was observed on the reciprocal shoulder mobility (0.89; 95% CI 0.81-0.94), 90/90 total body rotation (0.86; 95% CI 0.79-0.92), and lower body diagonal reach (0.85; 95% CI 0.78-0.91) tests of the ACS suggesting sufficient ability to identify musculoskeletal impairments and risk factors. The ACS is a simplistic screening tool that the coach can administer to discriminate between youth, high school, and college-level baseball players who possess musculoskeletal risk factors. The ACS subtests demonstrated high sensitivity for correctly identifying musculoskeletal risk factors common in baseball players and can be useful as a screening tool for baseball coaches developing arm care exercise programs. A field-expedient screen could provide coaches the ability to identify musculoskeletal risk factors that need to be addressed to minimize injury risk factors in a time-efficient manner.

The Management of Valgus Extension Overload Syndrome Experienced with Hitting in a High School Baseball Player: A Case Report.

BackgroundValgus extension overload syndrome (VEOS) of the elbow is a condition associated with overhead athletes. However, the non-surgical management of these individuals is not well documented.PurposeTo discuss the unique presentation, management, and outcomes of an adolescent baseball player with a chronic history of VEOS experienced during hitting.Case DescriptionA 15-year-old right-handed high school baseball catcher presented with a six-month history of right-sided ulnar elbow pain. Elbow MRI w/ contrast was consistent with VEOS. The initial examination demonstrated excessive resting right-sided humeral external rotation compared to his left. Valgus stress testing in the subject’s hitting position reproduced symptoms, which were alleviated with retest while correcting excessive humeral external rotation. Weakness of the humeral internal rotators and stiffness/shortness of the posterior shoulder were found and thought to relate to the humeral contribution to his elbow movement dysfunction. Rehabilitation emphasized addressing impairments contributing to excessive humeral external rotation with reintegration into batting.OutcomesAfter five weeks of physical therapy, the subject returned to soft toss hitting at approximately 75% velocity for the first time since symptom onset, without pain. At seven months after discharge, a phone conversation confirmed that the subject had returned to baseball without limitations.DiscussionDespite the concept of ‘regional interdependence’, common proximal impairments are often assumed to contribute to elbow pain without a clear biomechanical rationale. Future research demonstrating the specific biomechanical effects of the shoulder on the elbow is needed, in addition to more accessible examination strategies to assess their relationship.Level of Evidence5

Dietary self-efficacy and social support interactions in junior athletes' acquisition of life skills.

ObjectiveAccording to the stages of change, this study identified the association between dietary control self-efficacy and social support for healthy diets as factors influencing life skills acquisition in dietary habits among adolescents in Japan.Research designThis cross-sectional study was conducted between April and May 2018 among eight high school baseball teams in Japan.MethodParticipants included 180 Japanese high school baseball players. Survey items evaluated life skills (dependent variables), self-efficacy's influence on dietary control, social support (explanatory variables), and stages of change. Hierarchical multiple regression analysis was used to reveal the associations.ResultsIn the pre-action stage, although there was no significant association between the interaction of self-efficacy and social support on total life skills (β = 0.11, p = 0.158), a significant association was observed in the action/maintenance stage (β = 0.32, p < 0.05). The interaction between self-efficacy and social support showed a significant association with goal setting in the pre-action stage (β = 0.19, p < 0.05) and with communicating in the action/maintenance stage (β = 0.34, p < 0.05).ConclusionThe acquisition of life skills amidst dietary situations can be facilitated by providing social support that considers self-efficacy in relation to dietary control, according to the stages of change.

Increased external rotation related to the soft tissues is associated with pathologic internal impingement in high-school baseball players.

Changes in soft-tissue structures such as anterior laxity and posterior tightness are thought to contribute to the development of pathologic internal impingement in baseball players. Although side-to-side differences in shoulder rotational range of motion (ROM) is commonly used in clinical practice to quantify the soft-tissue changes, the ROM does not accurately reflect the soft-tissue changes because the ROM is affected not only by the soft tissues, but also by the bone. Increased retroversion of the humeral head is often observed in the dominant shoulder of throwing athletes. The purpose of this study was to determine the relationship between the soft-tissue-related (STR) ROM and pathologic internal impingement in baseball players. Bilateral humeral retroversion and ranges of glenohumeral external rotation (ER) and internal rotation (IR) were investigated in 81 high-school baseball players. The players were divided into two groups: the internal impingement group (19 players) and the control group (62 players). Humeral retroversion was measured using the ultrasound-assisted technique to assess the bone-related ER and IR. The STR ER and IR were defined as subtracting the amount of humeral retroversion from the measured ER andIR. The side-to-side difference (throwing shoulder-nonthrowing shoulder) in humeral retroversion showed no significant difference between the internal impingement group (6°±10°) and control group (11°±11°) (P=.064). The side-to-side difference in STR ER was significantly greater in the internal impingement group (12°±12°) than that in the control group (1°±14°) (P=.002). No significant difference was observed in the side-to-side difference in STR IR between the internal impingement group (-7°±16°) and control group (-5°±15°) (P=.696). Pathologic internal impingement was significantly associated with the side-to-side difference of STR ER (odds ratio, 1.06 for increase of 1°; 95% confidence interval, 1.02-1.11; P=.008). In high-school baseball players, the increased STR ER in the throwing shoulder may be associated with pathologic internal impingement. An increase of 10° in side-to-side difference in STR ER would increase the risk of pathologic internal impingement by 1.8 times.

Number of Months of Baseball in the Previous Year and Preseason Olecranon Tenderness: Risk Factors for Shoulder and Elbow Injuries in High-School Baseball Players.

To identify risk factors for shoulder and elbow injuries in high-school baseball position players and pitchers in the preseason history and physical examination. Retrospective cohort study. Community high-school baseball. Three hundred seventy-one male baseball players' mean age 15.0 ± 1.8 years. A preseason history and physical examination was performed on all athletes. Injury information was collected by weekly self-report and athletic trainer injury logs throughout the season. Comparisons between injured and noninjured players were performed using t tests and χ 2 analyses. Binary logistic regression models were developed to identify risk factors for injury. Seventy-six injuries were recorded over the season. In univariate analysis, the injured group had greater months of baseball participation ( P = 0.007) and shoulder visual analog scale for the past year ( P = 0.003). The injured group also had more olecranon tenderness ( P < 0.0001, odds ratio [OR] 2.9) and decreased elbow arc of motion. All other factors were not significantly different ( P > 0.05). In multivariable logistic regression, months per year of baseball participation was the only factor significantly associated with injuries ( P = 0.010, OR = 1.21). Baseball players who developed arm injuries during a season were more likely to play more months of baseball and report shoulder pain in the previous year. The presence of preseason olecranon tenderness was associated with nearly triple the risk of injury during the season. Every additional month of baseball participation in the previous year was associated with a 1.2× increased odds of injury. The presence of glenohumeral internal rotation deficit was not a predictor of injury.

Ultrasonographic appearance of the pronator quadratus muscle in high school baseball pitchers with and without elbow symptoms: a pilot study.

Earlier reports have described forearm flexor muscles as active stabilizers of the elbow to valgus stress during throwing motion. The pronator quadratus (PQ) muscle acts in coordination with the pronator teres muscle for forearm pronation. This study of high school pitchers was conducted to assess the association between sonographic appearance and a history of elbow symptoms. We examined 123 high school baseball pitchers, all of whom had completed a self-administered questionnaire, including items related to throwing-related elbow joint pain sustained during the prior year. Ultrasound examination was made of the pitchers with and without valgus stress of the medial aspect of the bilateral elbows. The sonographic appearance of the PQ was assessed on sagittal and axial images on the bilateral side. For participants with and without a history of elbow symptoms, we compared the maximum thickness of the PQ on sagittal and axial images of the throwing side. Regarding maximum thickness of the PQ on the sagittal and axial images, a significant difference was found between the throwing and non-throwing sides (throwing side vs non-throwing side mean: sagittal 6.3mm vs 5.7mm, axial 8.2mm vs 7.5mm, 95% confidence interval: sagittal 0.41-0.70, p < 0.001, axial 0.53-0.82, p < 0.001). The maximum thickness of the PQ on axial images with elbow symptoms was significantly greater than the PQ thickness of those without elbow symptoms. Nevertheless, no association was found between elbow valgus instability and the maximum thickness of the PQ on sagittal and axial images of the throwing side. Sonographic appearance of the PQ might be associated with elbow joint conditions in high school baseball players.

Shoulder and Elbow Injuries in Elite Taiwanese High School Baseball Pitchers From 2016 to 2017.

Background:Numerous studies have discussed the risk factors for shoulder and elbow injuries in high school baseball players worldwide.Purpose:To determine the risk factors for pitching-related shoulder and elbow injuries in Taiwanese high school pitchers.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Included in the study were 144 pitchers from 11 top-ranked Taiwanese high school baseball teams between 2016 and 2017 high school baseball season. The participants answered a 55-item questionnaire concerning physical characteristics, pitching activities, injury history, and off-season activities. Univariate analyses were conducted separately for participants with and those without a pitching-related injury in the 12-month study period. The chi-square test or Fisher exact test was applied to categorical variables, and the F test or t test was applied to continuous variables. A stepwise multivariate logistic regression analysis was used to identify factors related to pitching-related injuries, and those results were calculated as odds ratios (ORs).Results:Having a pitching-related injury was significantly related to the number of pitches per week in the past 12 months (OR, 1.01; P = .006), pain over the shoulder and/or elbow in the past 12 months (OR, 3.56; P = .008), pitching competitive baseball for more than 8 of the past 12 months (OR, 2.53; P = .036), throwing sliders (OR, 2.97; P = .026), and lack of participating in other over-the-shoulder activities (0.03-0.11 fewer odds; P ≤ .010).Conclusion:For elite high school pitchers in Taiwan, pitching-related shoulder and elbow injuries were related to the number of pitches per week, pitching competitive baseball for more than 8 of the past 12 months, pain over the shoulder and/or elbow in the past 12 months, throwing sliders, and a lack of participation in other sports with over-the-shoulder activities.

A Rehabilitation Progression for a Baseball Athlete Following Anterior Cruciate Ligament Reconstruction: A Case Report

Background Clinicians have long sought to return athletes safely and expeditiously to sport after anterior cruciate ligament reconstruction. No current literature exists showcasing the rehabilitation progression and testing battery that addresses the unique sport-specific demands of a high school baseball athlete. The purpose of this case study is to address a gap in the literature by providing an example of the postoperative management of a high school baseball player. Case Presentation An 18-year-old baseball player presented to physical therapy following anterior cruciate ligament reconstruction. He participated in a sport-specific 9-month course of rehabilitation. Outcome and Follow-Up The athlete was cleared for competitive baseball at 9 months post-surgery after completion of a comprehensive rehabilitation program and return-to-sport testing battery uniquely tailored toward the demands of his sport. Discussion The case study demonstrates the use of sport-specific rehabilitation strategies and return-to-sport testing for a high school baseball player. After a multidisciplinary consensus was reached regarding return-to-sport readiness, the athlete successfully returned to competitive baseball. JOSPT Cases 2022;2(2):64–84. doi:10.2519/josptcases.2022.10804

육상 피칭 트레이닝이 고등학교 야구선수의 구간속도 및 오버런 턴 각도에 미치는 영향

This study was to investigate the effects of athletics pitching training on section speed and overrun turn in high-school baseball players. In order to achieve the purpose of this study, baseball players at D high school, were selected at random and allocated 12 baseball players each for the Non Exercise group(NEG), Deficient Exercise group(DEG), Over Exercise group(OEG) and measured section speed and overrun turn before and after the experiment. The athletics pitching training program for 12 weeks. The athletics pitching training program for 12 weeks. The results of this study were as follows: First, As a result of analyzing the change of section speed according to athletics pitching training, OEG was significantly improved compared to NEG and DEG. Second, As a result of analyzing the change of overrun turn according to athletics pitching training, OEG was significantly improved compared to NEG and DEG.<BR> As conclusions, this study confirmed that the athletics pitching training on section speed and overrun turn in high-school baseball players. However, there is a need for more specific exercise programs to be developed for the continual improvement of athletic performance in athletics along with further studies to confirm the physiological benefits of those programs.

Plyometric training effects on physical fitness and muscle damage in high school baseball players.

[Purpose]The objective of this study was to investigate the effects of plyometric training on physical fitness and muscle damage in high school baseball players.[Methods]The participants in the study included 21 high school baseball players who are healthy and well-training. The participants were randomly allocated to the plyometric training (n=11) and control (n=10) groups. The plyometric training was applied 3 times a week for a total of 8 weeks and the control group took part in only regular baseball skills training without plyometric training. For physical fitness, measures included maximal strength (left and right hand-grip strength), muscle endurance (sit-up), agility (side-step), power (standing long jump), and balance (left and right Rhomberg test). For muscle damage, creatine kinase (CK) and lactate dehydrogenase (LDH) levels were measured.[Results]The results showed a significant interaction effect between time and groups in left hand-grip strength (P = 0.022), side-step (P = 0.004), and standing long jump (P < 0.001) after the 8-week plyometric training, with greater improvement in the plyometric training group than the control group. On the other hand, there was no significant interaction effect between time and groups in right hand-grip strength, situp, left and right Rhomberg test, CK level, and LDH level (P > 0.05).[Conclusion]In conclusion, 8-week plyometric training had a positive effect on improving physical fitness, such as maximal strength, agility, and power, in high school baseball players without causing additional muscle damage.

고등학교 야구 선수들의 상해 및 상해 이후 회복 특성에 대한 분석

The purpose of this study is to analyze the injury types and recovery characteristics after sports injuries of high school baseball players at each position. Four baseball teams of high schools located in Jeollanam-do were selected as population. A questionnaire was conducted with 84 high school baseball players to analyze sports injury characteristics. Frequency and percentage were verified using descriptive statistics to analyze injury characteristics. Cross-tabulation analysis(Chi-square, x2) was used to test the difference in injury parts at each position. The level of statistical significance was set at p＜.05. The following conclusions are drawn.<BR>The most frequent place of injury was the place for training. The highest injury part was an elbow and a shoulder. Injuries frequently occurred during group training and a sprain was the highest type of injury. The highest injury motion during games was pitching a ball. The most common reason for injury was self-carelessness.<BR>This study analyzed recovery characteristics after sports injuries in high school baseball players. As a result, the highest period for the return to play was 2-3 weeks and 4-5 months after injury. The response of complete treatment was high as 66.6%(‘agree’ and ‘strongly agree’). However, re-injury also occurred in more than half of respondents(58.3%).<BR>In conclusion, it is necessary to wear protective gear during training and devise injury prevention strategies to reduce the injuries of high school baseball players. The findings of this study will be helpful to develop and apply a conditioning program for season and off-season to prevent high school baseball players from injuries.

Match or mismatch between chronotype and sleep-wake cycle and their association with lean body mass gain among male high-school baseball players

ABSTRACT For athletes, it is important to acquire lean body mass (LBM) involving the skeletal muscle mass during their growth periods; however, the influence of chronotype on LBM gain remains unclear. We therefore aimed to investigate whether chronotype, sleep-wake cycle on weekdays (SWC-W), and their interaction contribute to LBM gain among adolescent male athletes in a 4-month intervention study. The participants were 45 male high-school baseball players. The intervention, including exercise menu (running and muscle strength training) and nutritional education, was conducted during a 4-month period of season-off training. The chronotype, body composition, lifestyle, and dietary intake were investigated before intervention (baseline) and after 4 months. Among the participants [Morningness (n = 14), Eveningness (n = 15), Intermediate (n = 16); ME score based on the Morningness/Eveningness Scale for Children (MES-C)], the midpoint of sleep on weekdays (MSW) was calculated in the “Morningness” and “Eveningness” participants, respectively. They were divided into 4 groups based on a match/mismatch with the chronotype: Type M-match (n = 8), Type M-mismatch (n = 6), Type E-match (n = 7), and Type E-mismatch (n = 8) groups. The data were compared among the 4 groups. Moreover, multiple regression analysis was conducted using an increase (kg) LBM gain as a response variable. When comparing the data between the “Morningness” and “Eveningness” participants, there were no differences in nutrient intake, the duration of training, or each parameter of body composition (per body weight) at baseline or after 4 months. There were also no differences in the rates of change in the body weight or each parameter of body composition. In groups in which the chronotype was consistent with the SWC-W (the Type M-match and Type E-match groups), the LBM gain were slightly greater than in the Type M-mismatch and Type E-mismatch groups (Type M-match: 3.5 ± 2.0 kg, Type M-mismatch: 1.6 ± 1.7 kg, Type E-match: 3.4 ± 2.2 kg, and Type E-mismatch: 1.2 ± 1.8 kg, p = .057). Multiple regression analysis revealed that an extent of the LBM gain was associated with a match between the chronotype and SWC-W (ß = 0.37, p = .030), independent of a long duration of training (ß = 0.52, p = .004). The results suggested that training-related LBM gain is associated with interactions between the chronotype and SWC-W in adolescent male athletes. Abbreviations: LBM: Lean body mass; SWC-W: Sleep-wake cycle on weekdays; ME score: Morningness-eveningness score; MES-C: Morningness/Eveningness Scale for Children; MSW: Midpoint of sleep on weekdays; MSF: Midpoint of sleep on free days; MSFsc: Midpoint of sleep on free days corrected for sleep debt accumulated through weekdays

The influence of chronic medial epicondylar apophysitis on medial ulnar collateral ligament insufficiency-: a retrospective cohort study.

BackgroundThis study aimed to investigate the effect of chronic traction apophysitis of the medial epicondyle (MEC) on medial ulnar collateral ligament (MUCL) insufficiency in high school baseball players.MethodsIn this retrospective cohort study, 3034 of 6069 high school baseball players were enrolled. A self-reported questionnaire was distributed to investigate past history of elbow pain and elbow pain during the previous season. Physical examinations to assess tenderness on the MUCL and the elbow valgus stress test (EVST) were performed. Ultrasonography was performed to determine the presence of morphological abnormalities of the anteroinferior aspect of the MEC (MEC lesions).ResultsParticipants with MEC lesions had a significantly higher prevalence of past history of elbow pain, elbow pain during the previous season, MUCL tenderness, and positive EVST than those without MEC lesions (P < .05). Multivariate logistic regression analysis revealed that the participants with the fragmented type had the highest risk of past history of elbow pain (odds ratio [OR] = 3.94), elbow pain during the previous season (OR = 2.27), positive EVST (OR = 3.49), and the second highest risk of MUCL tenderness (OR = 2.01) followed by the irregular type (OR = 2.31). Participants with the hypertrophic type had the lowest risk of past history of elbow pain (OR = 2.08), elbow pain during the previous season (OR = 1.42), MUCL tenderness (OR = 1.09), and positive EVST (OR = 1.47).ConclusionThe presence of chronic non-healed traction apophysitis of the MEC in high school baseball players presented a significantly high risk of elbow pain and MUCL insufficiency.

Relationships between Low Back Pain and Batting Practice in High School Baseball Players

Relationships between Low Back Pain and Batting Practice in High School Baseball Players

Changes in the psychological-competitive ability across three grades in high school baseball players aiming for the “KOSHIEN” tournament

Changes in the psychological-competitive ability across three grades in high school baseball players aiming for the “KOSHIEN” tournament

Wearing Rubber Bands on Hands Improves Shoulder Function of High School Baseball Players

Wearing Rubber Bands on Hands Improves Shoulder Function of High School Baseball Players