Sport-related concussions in baseball and softball: do mechanisms of injury affect recovery?

OBJECTIVE: Baseball and softball pose unique risks for sport-related concussion (SRC). Although these are not collision sports, concussions in baseball and softball can nonetheless involve high-speed impacts. In a regional, single-institution cohort of baseball and softball athletes who sustained an SRC, the current study sought to 1) describe the mechanisms of injury that led to SRC, and 2) compare initial symptom burden and recovery metrics across mechanisms, including time to return to learn (RTL), time to symptom resolution, and time to return to play (RTP) by mechanism of injury. METHODS: A retrospective cohort study was performed of baseball and softball athletes 12 to 23 years old who sustained an SRC between November 2017 and April 2022. Mechanisms of injury were divided into two categories: 1) contact mechanism (i.e., what initiated contact with the injured player, such as head-to-ball), and 2) player mechanism (i.e., the action the injured player was performing at the time of injury, such as fielding). The recovery outcomes of time to RTL, symptom resolution, and RTP were compared between mechanisms using bivariate analysis and multivariable regression analysis, controlling for sex, age, time to present to concussion clinic, and initial total symptom score. RESULTS: The sample included 58 baseball and softball players (60.3% female, mean age 16.0 ± 1.9 years). Most SRCs (62.1%) occurred during competition. Head-to-ball (50.0%) was the most common contact mechanism, followed by head-to-head/body (31.0%) and head-to-wall/ground/equipment (17.2%). Fielding (63.8%) was the most common player mechanism, followed by drills (20.7%) and running (13.8%). SRCs sustained in practice had significantly longer RTL (median 10.0 [interquartile range (IQR) 3.3-16.3] vs 4.0 [IQR 2.0-8.0] days; U = 421.5, p = 0.031) and symptom resolution (37.0 [IQR 18.0-90.0] vs 14.0 [IQR 7.0-41.0] days; U = 406.5, p = 0.025) compared with SRCs sustained in competition. Multivariable regression analysis revealed that head-to-wall/ground/equipment contact mechanism was associated with longer RTL (ß = 0.30, 95% CI 0.07-0.54, p = 0.013). CONCLUSIONS: The current study found that SRCs in baseball and softball occurred more often in competition than in practice. Head-to-ball and fielding were the most common contact and player mechanisms, respectively. SRCs sustained in practice were associated with longer time to RTL and symptom resolution, and head-to-wall/ground/equipment was associated with longer RTL in multivariable regression analysis. These results provide empirical data to improve concussion safety in baseball/softball.

Strength, speed, and anthropometric predictors of in-game batting performance in baseball.

A key focus of sports science research is the identification of quantitative assessments that can predict players' on-field performance and developmental potential. Despite efforts to establish predictive models, there are few validated measures that show reliable associations and large gaps in understanding. Here, we test a multidimensional battery of assessments developed through the USA Baseball, Prospect Development Pipeline that capture strength and functional movement abilities, and anthropometric characteristics, in a two-year cohort of collegiate baseball players from the Appalachian League. Swing propensity metrics for Zone Contact Percentage (ZCP: proportion pitches in strike zone swung at and hit) and Hard-Hit Percentage (HHP: proportion in-play balls with exit velocity ≥ 95 mph) were calculated on 189 players. Models testing hierarchical combinations of anthropometric and anthropometric plus assessment data were implemented using nested cross-validation with random forest and elastic net regression. Results indicate that anthropometric features account for 29% of variance in ZCP and 50-55% of HHP, while the addition of assessment contributed an additional 1-3% to ZCP and 5-12% to HHP, with top predictors coming from PDP strength and power assessments. These findings delineate contributions of andromorphic and physical abilities to in-game baseball performance using a validated assessment battery and advanced game statistics.

The effects of jaw clenching and mouthpiece use on bat swing velocity in Division II athletes.

Research assessing the effects of mouthpieces on an individual's aerobic, anaerobic, or muscular performance have attributed cited improvements to the participant's ability to jaw clench. Jaw clenching research finds positive outcomes with the task of jaw clenching with targeted muscle groups in a controlled laboratory setting. Thus, the study's goal was to determine if the addition of a mouthpiece would positively affect performance outcomes in a field-based whole-body muscle movement. Fourteen participants (8=F and 6=M) NCAA softball and baseball athletes completed 5 maximal bat swings with and without a mouthpiece in 4 conditions: no jaw clenching (NC), mouthpiece and jaw clenching (MP+C), mouthpiece only (MP), and jaw clenching only (C). Significant differences occurred in conditions, with the highest velocity noted in the combined condition of MP+C (71.9 mph) as compared to NC (67.9 mph), MP (68.6 mph), and C (70.9 mph). A repeated measures ANOVA demonstrated significant differences with bat swing velocity (F = 13.19, df 3, p < 0.0001). Pairwise comparisons revealed significant differences in MP+C with MP (p = 0.007); MP+C with NC (p = 0.001), and C with NC (p = 0.009). The results of this study provide evidence of jaw clenching's positive effects on the dynamic, whole-body explosive activity of a bat swing.

Using a Sensor-Embedded Baseball to Identify Finger Characteristics Related to Spin Rate and Pitching Velocity in Pitchers.

BACKGROUND: Previous investigations have shown a positive relationship between baseball pitching velocity and the kinetic chain involved in pitching motion. However, no study has examined the influence of finger characteristics on pitching velocity and rate of spin via a sensor-embedded baseball. METHODS: Twenty-one pitchers volunteered and were recruited for this study. An experimental baseball embedded with a force sensor and an inertial measurement unit was designed for pitching performance measurement. Finger length and strength were measured as dependent variables. Spin rate and velocity were independent variables. Pearson product-moment correlations (r) and intraclass correlation coefficients (ICCs) determined the relationship between finger characteristics and pitching performance. RESULTS: Finger length discrepancy, two-point pinch strength, index finger RFD (rate of force development), middle finger impulse, and force discrepancy had significant correlations with spin rate (r = 0.500~0.576, p ≤ 0.05). Finger length discrepancy, two-point pinch, three-point pinch strength, index and middle finger RFD, middle finger impulse, and force combination had significant correlations with fastball pitching velocity (r = 0.491~0.584, p ≤ 0.05). CONCLUSIONS: Finger length discrepancy, finger pinch strength, and pitching finger force including maximal force and RFD may be factors that impact fastball spin rate and fastball pitching velocity.

Countermovement Jump and Momentum Generation Associations to Fastball Velocity Performance Among Division I Collegiate Pitchers.

ABSTRACT: Sakurai, M, Qiao, M, Szymanski, DJ, and Crotin, RL. Countermovement jump and momentum generation associations to fastball velocity performance among Division I collegiate pitchers. J Strength Cond Res 38(7): 1288-1294, 2024-The current study explored the relationships between countermovement jump (CMJ) profiles and baseball pitching performance. Nineteen Division I collegiate pitchers performed in-laboratory pitching and bilateral CMJs. Whole-body kinematics and ground reaction force were collected during both pitching and CMJ evaluations. Statistically significant correlations of concentric impulse and peak power in the CMJ test with fastball velocity were observed (r = 0.71 and 0.68). Concentric impulse in CMJ also showed a statistically significant correlation with linear momentum in the anterior-posterior direction during pitching (r = 0.68). Lean body mass and body mass showed statistically significant correlations with both of the 2 linear momentums during pitching (r = 0.71∼0.83), and concentric impulse in CMJ (r = 0.71 and 0.81). Pelvis and trunk pitching mechanics did not correlate with any of the CMJ variables at the statistically significant level, whereas the direction of the correlations varied (|r| < 0.45). Assessment of a baseball pitcher's CMJ should focus on concentric impulse and peak power because only these showed meaningful relationships with fastball velocity or momentum generation during pitching. An increase in lean body mass is also suggested to be able to generate more impulse and momentum. Baseball coaches, strength coaches, and clinicians are encouraged to include lower-body explosive training to enhance the force and power output capacity of baseball pitchers.

Performance and Return to Play After Surgery for Thoracic Outlet Syndrome in Professional Baseball Players: A Matched Cohort Analysis.

BACKGROUND: Thoracic outlet syndrome (TOS) remains a rare diagnosis but is being recognized as a cause of upper extremity dysfunction in professional baseball players. PURPOSE/HYPOTHESIS: The purpose was to determine performance and return-to-play (RTP) outcomes in professional baseball players after surgical treatment of TOS. The hypothesis was that there would be a high RTP rate in professional baseball players after TOS surgery with no statistical differences in performance between pitchers who had TOS surgery and matched controls. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All professional baseball players who underwent surgical treatment of TOS between 2010 and 2017 were identified using the Major League Baseball Health and Injury Tracking System database. Demographic and performance data (before and after surgery) for each player were recorded. Performance variables were then compared between players who underwent TOS surgery and matched controls. The matching criteria were no history of previous surgeries on affected arm, age at time of surgery, throwing side, level of play (Major or Minor League Baseball), and years of experience playing professional baseball. RESULTS: Overall, 52 players underwent surgery for TOS, of whom 46 (88%) were pitchers. The type of TOS was neurogenic in 69% and venous in 29%. One player had arterial TOS. After TOS surgery, 79% of players returned to play at the same or higher level (RTSP) by 9.5 months and played ≥3 years after surgery. No differences were found in RTSP rate based on the type of TOS. No statistical difference was found in RTP rates between major and minor league players. Pitchers had a 76% RTSP, which was similar to the natural attrition for control pitchers (P = .874). After TOS surgery, pitchers saw a decline in several performance metrics, but these declines were not different from those of control pitchers, indicating that the decline in performance after TOS surgery was no faster than is seen in healthy professional pitchers as they age. CONCLUSION: The rate of RTSP after surgery for TOS in professional baseball players was 79%. There was no difference in RTP based on the type of TOS. Pitchers who underwent surgery for TOS had no significant differences in pitching performance metrics after surgery compared with matched controls.

The Validity and Reliability of a Real-Time Biofeedback System for Lumbopelvic Control Training in Baseball Players.

BACKGROUND: This study validates real-time biofeedback for lumbopelvic control training in baseball. The lumbopelvic region is crucial for generating kinetic energy in pitching. Real-time biofeedback enhances training effectiveness and reduces injury risk. The validity and reliability of this system were examined. PURPOSE: This study was to investigate the validity and reliability of the real-time biofeedback system for lumbopelvic control training. METHODS: Twelve baseball players participated in this study, with data collected in two sessions separated by a week. All participants needed to do the lateral slide exercise and single-leg squat exercise in each session. Pelvic angles detected by the real-time biofeedback system were compared to the three-dimensional motion capture system (VICON) during training sessions. Additionally, pelvic angles measured by the biofeedback system were compared between the two training sessions. RESULTS: The real-time biofeedback system exhibited moderate to strong correlations with VICON in both exercises: lateral slide exercise (r = 0.66-0.88, p < 0.05) and single-leg squat exercise (r = 0.70-0.85, p < 0.05). Good to excellent reliability was observed between the first and second sessions for both exercises: lateral slide exercise (ICC = 0.76-0.97) and single-leg squat exercise (ICC = 0.79-0.90). CONCLUSIONS: The real-time biofeedback system for lumbopelvic control training, accurately providing the correct pelvic angle during training, could enhance training effectiveness.

Prevalence of impaired foot function in baseball players with and without disabled throwing shoulder/elbow: a case-control study.

Prevalence of impaired foot function among baseball players with and without a disabled throwing shoulder/elbow was investigated. The study included 138 male players. Players who had previously complained of shoulder/elbow pain during throwing motion were defined as the players with a history, and those who experienced shoulder/elbow pain during the examination were defined as having the injury. Foot function was evaluated by foot "rock paper scissors" movements and floating toes. Their prevalence was assessed and the relationships between players with and without the injuries were statistically analyzed. The prevalence of players with a history and injury was 27% and 7%, respectively. The prevalence of impaired foot function on the non-throwing side among players with injury was significantly higher than those without (60% vs. 28%, P < 0.001) and higher tendency on the throwing side than those without (60% vs. 32%). Regarding floating toes, players with a relevant history showed a significantly higher prevalence on the throwing side than those without (49% vs 28%, P < 0.001) and higher tendency on the non-throwing side than those without (49% vs 32%). Players with disabled throwing shoulder/elbow have a significantly higher prevalence of impaired foot function and floating toes than players without it.

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.

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.

Classifying batted ball outcomes from Division I collegiate baseball players.

Modern technology challenges anecdotal beliefs on baseball performance. The study's purpose examines these beliefs by classifying batted ball outcomes. Three categories of independent variables (anthropometry, in-game situation, technique-based), from 1,922 batted ball outcomes produced by 230 players, were used to classify the likelihood of hits during 2021 college baseball games. Anthropometry included player's heights and weights. In-game situation entailed batter side, same side, ahead count, and pitch type. Technique-based variables measured by TrackMan radar included exit speed (ExSp), launch angle (LA), batted ball distance (BBD), and hang time (HT). Binary logistic regression analysis was performed with batted ball outcome as the dependent variable. Independent variables provided a good fit (χ2 (10) = 522.358, p < 0.01) and correctly classified nearly three-fourths of outcomes. Height (ß = 0.030, p < 0.05), ExSp (ß = 0.023, p < 0.05), LA (ß = 0.028, p < 0.01), and BBD (ß = 0.067, p < 0.01) each had significant positive associations, yet HT (ß = -1.661, p < 0.01) had a significant negative association, with batted ball outcomes. TrackMan provided four significant independent variables. Anthropometry's contribution to batting outcome was modest, while in-game situation's impact was non-significant; results contradict anecdotal beliefs of their importance.

Assessing the COVID-19 pandemic's impact on pediatric baseball and basketball-related craniofacial and neck injuries treated in United States emergency departments, 2003-2022.

BACKGROUND: A large proportion of United States (U.S.) youth play basketball, baseball, softball, or T-ball. Each of the activities poses a documented risk of craniofacial and neck injuries. However, few studies have assessed the national prevalence of pediatric craniofacial and neck injuries in this population, particularly following the COVID-19 pandemic. METHODS: The National Electronic Injury Surveillance System (NEISS) dataset was used to identify pediatric craniofacial and neck injuries associated with basketball, baseball, softball, or T-ball from 2003-2022 in a cross-sectional study. The annual number of injuries before and after the onset of the COVID-19 pandemic with 95% confidence intervals were calculated. Interrupted time series analysis (ITSA) was used to estimate the pandemic's impact on the monthly number of injuries incurred nationally. RESULTS: Both overall and stratified by sport involvement, the annual number and rate of injuries identified in NEISS decreased significantly after the COVID-19 pandemic. ITSA demonstrated that the monthly number of injuries decreased -4094.4 (95% CI = -5100, -3088.7) immediately after the beginning of the pandemic. The number of injuries began increasing towards pre-pandemic levels at a rate of 110.6 (95% CI = 64, 157.2) injuries per month after the initial plunge. CONCLUSION: Prior to the-pandemic, there was a steady decline in craniofacial and neck injuries due to basketball, baseball, softball and T-ball among children, aged <18 years. The shutdown during the initial months of the COVID-19 pandemic resulted in a precipitous drop in such injuries. Current rates are approaching pre-pandemic levels and may exceed them. Continued efforts are needed to keep the pre-pandemic progress.

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update).

ABSTRACT: Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

Comparison of Windup and Stretch Pitching Biomechanics in Baseball With Implications for Safety and Performance.

BACKGROUND: Historically, it was assumed by some that high leg lift with windup pitching generated more ball velocity whereas pitching from the stretch was quicker to reduce the risk of base stealing but also more stressful on the arm. However, many now believe that velocity and stress do not differ between windup and stretch and always pitching from the stretch is simpler than mastering 2 techniques. PURPOSE/HYPOTHESIS: The purpose of this study was to compare windup and stretch fastball pitching biomechanics. It was hypothesized that there would be statistically significant and clinically important differences in ball velocity, timing of angular velocities, joint kinetics, and pitching kinematics. STUDY DESIGN: Controlled laboratory study. METHODS: Fastball pitching biomechanics previously captured for 221 healthy baseball pitchers (105 professional, 52 collegiate, and 64 high school level) were analyzed. For each pitcher, data for 3 to 10 windup trials and 3 to 10 stretch trials were available. Ball velocity was recorded using a radar gun. A 12-camera, 240-Hz automated motion capture system was used to track 39 reflective markers attached to the pitcher. A total of 24 kinematic parameters, 4 temporal parameters, and 5 kinetic parameters were calculated. Data for each parameter were compared across the 2 techniques and 3 competition levels using 2-way repeated-measures analysis of variance (P < .01). Based on previous studies and the expertise of the investigators, the minimal clinically important difference (MCID) was set as 2° for angle measurements, 20 deg/s for angular velocities, 0.5 m/s for fastball velocity, and 0.3% body height × weight for normalized joint torque. RESULTS: Fastball velocity was statistically greater from the windup than stretch for the collegiate subgroup but not for the other 2 levels. The collegiate level difference was below the MCID. Pitching from the windup generated greater front knee height and required more time from initiation of leg lift to front foot contact. From foot contact to ball release, there were 11 additional small, statistically significant differences between windup and stretch; however, each of these was well below the MCID. CONCLUSION: Pitching from the stretch was quicker and should be used with runners on base to prevent stealing. Pitching from the windup and stretch produced similar ball velocity, joint kinetics, and kinematics. Thus, pitchers may choose to use both techniques or stretch only based on comfort and personal preference. CLINICAL RELEVANCE: The decision to pitch from both the windup and stretch or only from the stretch should not affect a pitcher's performance or joint stress (and injury risk).

Facial trauma in the major league baseball.

OBJECTIVE: The objectives of this study were to identify and describe significant facial trauma present in Major League Baseball (MLB) that resulted in players missing games or being placed in the injury reserve list. STUDY DESIGN: This was a retrospective cohort study. The predictor variables were the player's age, height, weight, body mass index, position, team conference, and if played games took place in playoffs season. The outcome variables were injury location (upper, middle, and lower facial third) and type of injury (soft tissue, fracture). Chi-square and logistic regression were computed to determine associations between predictor and outcome variables. RESULTS: A total of 109 players missed games due to facial injuries, and a total of 115 injuries were identified. Of the 115 injuries, none occurred in the upper facial third, 96 (83%) were in the middle third, and 19 (17%) in the lower third. Most fractures occurred in fielders (45%), and most soft tissue injuries in basemen (40%). CONCLUSIONS: Significant facial trauma in the MLB has risen in recent years. The player's height, conference, and playoff season were the most associated factors. Most injuries occurred in the periorbital area. A recommendation for the use of protection goggles can be made to prevent them.

Altered Cervical Spine Position Results in Decreased Eccentric Shoulder Rotation Strength.

Overhead athletes require strenuous shoulder activity in nonneutral cervical spine positions to eccentrically decelerate the throwing/striking arm following ball release/contact. We therefore aimed to compare eccentric shoulder rotation strength through a 90° arc between neutral and rotated positions. Fifty-two participants (19 M, 34 F 170±10 cm; 73±18 kg, 21.9±2.9 years) without shoulder or cervical spine pathology participated. Isokinetic eccentric shoulder rotation strength was measured through a 90° arc with the shoulder elevated 90° in frontal plane (frontal plane), and 45° anterior to the frontal plane (scapular plane) in neutral and rotated cervical spine positions. Cervical spine position was obtained by instructing participants to maximally rotate their respective side. Frontal plane eccentric external rotated strength differed between neutral and contralaterally positions in the first 10° of the motion, near forearm vertical (p+=+0.029). Internal rotation strength differed between neutral and contralaterally rotated positions from 55-60° external rotation (p+=+0.004). Scapular plane eccentric external rotation differed between cervical positions between 21-67° shoulder external rotation (p<0.001). Scapular plane internal rotation strength differed between cervical positions between 22-60° shoulder external rotation (p<0.001). In populations requiring strenuous use of their shoulders in altered cervical spine positions, sports medicine clinicians should consider including strength testing that reflects the functional positions of their patients during an orthopedic examination.

Feasibility of the pitch efficiency rating: A novel tool for systematic assessment of pitching mechanics in developing throwing athletes.

BACKGROUND: Injuries in younger baseball athletes continue to increase despite work characterizing risk factors. Three-dimensional (3D) motion capture may identify suboptimal pitching mechanics that predispose an athlete to injury, but 3D-motion analysis is often inaccessible. Thus, there is a gap between the current biomechanics literature and its practical application in young athletes. The current study aims to assess the reliability of the pitch efficiency rating (PER) as a systematic tool to evaluate throwing mechanics in developing baseball pitchers. OBJECTIVE: To determine the feasibility of application and reliability of a novel, scientifically informed tool (PER) for the assessment of pitching mechanics. DESIGN: Reliability study using Bland-Altman methods for assessing agreement between two raters. SETTING: Academic medical center through community outreach. PARTICIPANTS: Pitching mechanics were assessed and rated with the PER for 40 athletes (26 high school, 14 Division III), average age 19.0 years old (range 15.3-23.7 years old). INTERVENTIONS: N/A. MAIN OUTCOME MEASURES: Interrater and intrarater reliability as calculated by intraclass correlation coefficient (ICC). RESULTS: For initial readings comparing interrater reliability between Rater 1 and Rater 2, the ICC was calculated at 0.80 (95% confidence interval [CI] 0.66-0.89) and 0.76 (95% CI 0.60-0.86) for the second set of ratings. Regarding intrarater reliability across reads, ICC was found to be 0.63 (95% CI 0.43-0.79) for Rater 1, and 0.91 for Rater 2 (95% CI 0.85-0.95). CONCLUSIONS: The present study introduces the PER as a potential tool for evaluating pitching mechanics. However, the intrarater reliability of the PER did not meet preestablished criteria in one of the two pilot raters. Further study is needed to continue to assess the reliability of the tool across diverse demographics.

Electromyographic analysis of shoulder-complex muscles performing overhead presses with dumbbell, kettlebell, and bottom-up kettlebell.

INTRODUCTION: Kettlebell exercises, specifically the bottom-up grip, have become increasingly popular in training programs. The purpose of this research was to determine if a bottom-up kettlebell grip favorably alters the electromyography (EMG), activity in the medial deltoid (MD), serratus anterior (SA), and lower trapezius (LT), muscles compared to using a dumbbell or traditional kettlebell grip during overhead shoulder presses. METHODS: Twenty-eight healthy, male, Division III collegiate baseball players (mean age = 19.8 ± 1.28 years) performed five overhead presses of equal weight, 11.34 kg (25 lbs), using a dumbbell (DB), kettlebell w/traditional grip (KB), and kettlebell held with a bottom-up grip (KBU). RESULTS: For the MD, there was significantly greater EMG activity using the DB compared to KBU, but no significant differences between the DB and KB, or KB and KBU. For the SA, greater EMG activity was noted using the KBU compared to KB, and KBU compared to DB, but no differences between KB and DB. For the LT, greater EMG activity was noted using the DB compared to KB, but no differences between DB and KBU, or KB and KBU. CONCLUSION: The KBU press only elicited greater EMG activity in the SA. The DB elicited greater EMG activity in both the MD and LT. Shoulder-complex EMG activity varies with different types of overhead presses using equivalent loads.

Shoulder kinetic during pitching in baseball players with scapular dyskinesis.

INTRODUCTION: Shoulder injuries in baseball players cause excessive shoulder load during pitching and scapular dyskinesis (SD). However, the characteristics of pitching kinetics in the shoulder joint with SD are unclear. This study aimed to investigate the effect of SD on pitching kinetics in the shoulder joint of baseball players. METHOD: Seventy-two college and independent league baseball players participated in the study. The pitching motion was measured using an 18-camera motion-capture system. SD was classified into four types (I-IV) using the scapular dyskinesis test (SDT). The pitching kinetics data were analyzed. RESULTS: The agreement of SD in this study was 56/72 (77.8%). SD were classified into 31 abnormal group (type I-Ⅲ) and 25 control group (type Ⅳ). Three participants with measurement failure during the pitching motion analysis were excluded from the analysis. The abnormal group showed a larger maximum value of the glenohumeral normalized anterior joint force than the control group. CONCLUSIONS: These results suggest that an increase in GH anterior force during pitching causes an excessive increase in external rotation of the GH with an insufficient posterior tilt of the scapula with SD. Therefore, baseball pitching with SD may involve shoulder injuries owing to excessive shoulder load during pitching.