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The longevity of Baseball Hall of Famers compared to other players.

The authors compared the longevity of all baseball players alive at the time of their induction into the Baseball Hall of Fame with age-matched controls who were likewise alive at the time of the Hall of Famer's induction, and also matched them for career length, player position, and body-mass index, to assess if fame in sports is associated with increased longevity. Median post-induction survival for Hall of Famers was 5 years shorter than for noninducted players (18 vs. 23 years, respectively). In a second analysis, significantly more Hall of Famers died of cardiovascular or stroke causes than other players for whom cause of death was known. Baseball fame may have a hitherto unrecognized price.

Awards and Prizes↗

Accuracy of qualitative analysis for assessment of skilled baseball pitching technique.

Baseball pitching must be performed with correct technique if injuries are to be avoided and performance maximized. High-speed video analysis is accepted as the most accurate and objective method for evaluation of baseball pitching mechanics. The aim of this research was to develop an equivalent qualitative analysis method for use with standard video equipment. A qualitative analysis protocol (QAP) was developed for 24 kinematic variables identified as important to pitching performance. Twenty male baseball pitchers were videotaped using 60 Hz camcorders, and their technique evaluated using the QAP, by two independent raters. Each pitcher was also assessed using a 6-camera 200 Hz Motion Analysis system (MAS). Four QAP variables (22%) showed significant similarity with MAS results. Inter-rater reliability showed agreement on 33% of QAP variables. It was concluded that a complete and accurate profile of an athlete's pitching mechanics cannot be made using the QAP in its current form, but it is possible such simple forms of biomechanical analysis could yield accurate results before 3-D methods become obligatory.

Adolescent↗

Prevention of commotio cordis in baseball: an evaluation of chest protectors.

BACKGROUND: In a recent study of fatal chest impacts by baseballs, 28% of the children were wearing a chest protector. This study evaluates the effectiveness of chest protectors in reducing the risk of commotio cordis. METHODS: Five commercially available chest protectors were placed on a three-rib structure simulating the chest and impacted at 40, 50, 60, and 70 miles per hour by a standard baseball. Ten repeated tests were conducted on each vest in random order, and on the control (unprotected chest). The viscous response (or viscous criterion [VC]) was used to assess differences in fatality risk. RESULTS: One vest had a statistically lower VC (average, 50.6%, p < 0.05) for all impact speeds. Three averaged 18.7% to 27.7% lower VC, but were significantly different only at higher speeds. One vest had an average 34.2% higher VC, and was significantly higher at 40 to 50 miles per hour (p < 0.05). A method was proposed linking laboratory test results to real-world incidents of ventricular fibrillation. CONCLUSIONS: The majority of commercially available chest protectors fail to provide consistent reductions in commotio cordis risk. Nonetheless, there are benefits from their use in baseball until improved safety equipment is developed and standard tests are established to assess sport equipment effectiveness.

Athletic Injuries↗

The influence of baseball modulus and mass on head and chest impacts: a theoretical study.

Although not common, injuries that result in death do occur in youth baseball. Specifically, in the 5- to 14-year old age group a total of 68 deaths between 1973 and 1995 have been directly attributed to impacts from baseballs to the head and chest. The purpose of this work was to determine the effect of lowering ball modulus and ball mass on the likelihood of reducing impact injury. A theoretical model, based upon the assumption of ideal elastic behavior, was used to calculate the impact response of the head. At a constant ball velocity, lowering both modulus and mass had the greatest influence in decreasing peak head acceleration, Gadd Severity Index, and Head Injury Criterion. Independently lowering the modulus or the mass decreased the impact variables and the estimates of injury, but the decreases varied with the specific impact variable and injury criterion. To study the impact response of the ball and chest, an existing viscoelastic lumped-element model of the chest was used. Lowering ball modulus and mass had various effects, e.g., lowering ball modulus did not affect peak sternal displacement, but it did decrease peak sternal velocity. These theoretical models aid in illustrating that impact response depends upon ball modulus and mass, the physical properties of the target, and the specific impact variable studied. This theoretical model suggests that a softer and lighter than traditional baseball would be the most likely ball model to minimize impact injuries because this ball consistently reduced all impact response variables studied. Since impact injury criteria for youths are presently not validated, the degree to which impact injuries may be reduced remains uncertain.

Adolescent↗

Batting performance of wood and metal baseball bats.

INTRODUCTION/PURPOSE: Although metal baseball bats are widely believed to outperform wood bats, there are few scientific studies which support this. In a batting cage study, Greenwald et al. found that baseballs hit with a metal bat traveled faster than those hit with a wood bat, but the factors responsible for this difference in bat performance remain unidentified. The purpose of this study was to determine the effects of swing speed, impact location, and elastic properties of the bat on batted ball speeds. METHODS: The pitched ball, batted ball, and swings of two wood and five metal baseball bats by 19 different players were tracked in three dimensions at 500 Hz using a passive infrared motion analysis system. RESULTS: Increases in the batted ball speeds of metal bats over those of wood bats resulted from faster swing speeds and higher elastic performance with an apparent increase in the ball-bat coefficient of restitution. The contribution of these variables to batted ball speed differed with metal bat model. The "sweet spot" associated with maximum batted ball speeds was located approximately the same distance from the tip of wood bats as it was from metal bats. CONCLUSIONS: The variables that correlated with differences between metal and wood bat performance, and most notably differences in the percentage of faster batted balls, were identified using a novel kinematic analysis of the ball and bat. These variables and their correlation with bat performance should be applicable to other players and bats, although more skilled players and higher performing bats would likely result in even faster batted ball speeds.

Acceleration↗

The prevention of baseball and softball injuries.

Forty million individuals participate in organized softball leagues each year in the United States. Eighteen million additional student athletes and young adults also participate in organized baseball league play. In addition to being two of the most popular team sports in the United States, they also are responsible for a significant percentage of sports-related injuries that are sustained in the United States. Fortunately, numerous interventions independently have been shown to be effective at reducing the injury scenario, which has grown to be of epidemic proportion. Interventions such as break-away bases, batting helmets, face shields on helmets, lighter mass baseballs, and teaching and reiteration of the fundamentals of softball and baseball all have been effective in preventing millions of injuries and billions of dollars in healthcare costs each year in the United States.

Accident Prevention↗

"Markov at the bat": a model of cognitive processing in baseball batters.

Anecdotal evidence from players and coaches indicates that cognitive processing (e.g., expectations about the upcoming pitch) plays an important role in successful baseball batting, yet this aspect of hitting has not been investigated in detail. The present study provides experimental evidence that prior expectations significantly influence the timing of a baseball swing. A two-state Markov model was used to predict the effects of pitch sequence and pitch count on batting performance. The model is a hitting strategy of switching between expectancy states using a simple set of transition rules. In a simulated batting experiment, the model provided a good fit to the hitting performance of 6 experienced college baseball players, and the estimated model parameters were highly correlated with playing level.

Adult↗

Dynamic US of the anterior band of the ulnar collateral ligament of the elbow in asymptomatic major league baseball pitchers.

PURPOSE: To determine whether dynamic ultrasonography (US) can reveal abnormalities of the anterior band of the ulnar collateral ligament (UCL) of the elbow in asymptomatic major league professional baseball players. MATERIALS AND METHODS: US was performed in 26 asymptomatic major league professional baseball pitchers before spring training. Images were obtained in both pitching and nonpitching arms with a multifrequency 13-MHz linear-array transducer. The thickness of the anterior band of the UCL and the width of the joint it spans (the ulnohumeral joint) were measured with the elbow at 30 degrees of flexion, both at rest and with valgus stress. The thickness of the anterior band of the UCL and the width of the joint space were compared for pitching and nonpitching arms by using the Student t test. The prevalence of hypoechoic areas and calcifications within the anterior band of the UCL in pitching and nonpitching arms was compared by using the McNemar test. The average time of the US examinations was recorded. RESULTS: At rest, the mean thickness (+/- 1 SD) of the anterior band of the UCL was 6.3 mm +/- 1.1 in pitching arms and 5.3 mm +/- 1.0 in nonpitching arms. This difference was statistically significant (P <.01). With stress, the anterior band thickness was 6.3 mm +/- 1.4 in the pitching arms and 4.8 mm +/- 0.9 in the nonpitching arms (P <.001). The joint space width at rest was 2.8 mm +/- 1.0 in the pitching arms and 2.5 mm +/- 0.7 in the nonpitching arms (not statistically significant). When stress was applied, however, the joint space width was significantly greater in the pitching arms than in the nonpitching arms (4.2 mm +/- 1.5 vs 3 mm +/- 1.0, respectively; P <.01). Hypoechoic foci within the anterior band of the UCL were seen in 18 of 26 (69%) pitching arms and three of 26 (12%) nonpitching arms (P <.001). Calcifications were detected in nine of 26 (35%) pitching arms but in none of the nonpitching arms (P <.001). The average time for bilateral US was 10.4 minutes. CONCLUSION: Dynamic US provides a rapid means for evaluating the anterior band of the UCL in professional baseball pitchers. In pitching arms, this band is thicker, is more likely to have hypoechoic foci and/or calcifications, and demonstrates more laxity with valgus stress.

Adult↗

Trajectory interpretation by supplementary eye field neurons during ocular baseball.

Good performance in the sport of baseball shows that humans can determine the trajectory of a moving object and act on it under the constraint of a rule. We report here on neuronal activity in the supplementary eye field (SEF) of monkeys performing an eye movement task inspired by baseball. In "ocular baseball," a pursuit eye movement to a target is executed or withheld based on the target's trajectory. We found that a subset of neurons in the SEF interpreted the trajectory according to the task rule. Other neurons specified at a later time the command to pursue the target with the eyes. The results suggest that the SEF can interpret sensory signals about target motion in the context of a rule to guide voluntary eye movement initiation.

Animals↗

Humeral retroversion and its relationship to glenohumeral rotation in the shoulder of college baseball players.

BACKGROUND: Previous studies have documented changes in musculature, bony anatomy, and glenohumeral rotation in the dominant shoulder of baseball players. HYPOTHESIS: In a group of asymptomatic college baseball players the total range of motion in the dominant and nondominant shoulders will be similar. Any measured increase in external rotation and decrease in internal rotation occurring between the two sides will be consistent and directly correlate with an increased angle of humeral retroversion in the dominant extremity. STUDY DESIGN: Descriptive anatomic study. METHODS: Fifty-four asymptomatic college baseball players were examined. Standard measurements of glenohumeral range of motion were made and humeral retroversion was determined radiologically. RESULTS: Total rotational motion, measured at 90 degrees of glenohumeral abduction, was 159.5 degrees for the dominant shoulders and 157.8 degrees for the nondominant shoulders. Mean differences in external and internal rotation in the dominant versus nondominant extremities were 9.7 degrees and 8.2 degrees, respectively. Humeral retroversion measured 36.6 degrees +/- 9.8 degrees in the dominant and 26 degrees +/- 9.4 degrees in the nondominant extremity. The mean difference in retroversion correlated significantly by Pearson's product moment with the difference in external (P = 0.001) and internal (P = 0.003) rotation measurements. CONCLUSIONS: There is a pattern of increased external rotation and decreased internal rotation in the dominant extremity that significantly correlates with an increase in humeral retroversion. The loss of internal rotation and gains in external rotation may be more strongly related to adaptive changes in proximal humeral anatomy than to changes in the soft tissues.

Adolescent↗

Evidence of subclinical medial collateral ligament injury and posteromedial impingement in professional baseball players.

BACKGROUND: Recognition and treatment of elbow conditions such as medial collateral ligament injury and posteromedial impingement are increasing in throwing athletes. Magnetic resonance imaging may provide pivotal information in the management of these athletes. Knowledge of the utility of magnetic resonance imaging has become widespread throughout the baseball community. However, data on the frequency and extent of asymptomatic magnetic resonance imaging findings in the elbows of this throwing population are lacking . HYPOTHESIS: Abnormalities in the throwing elbows of asymptomatic professional baseball players compared to the nonthrowing elbows are frequently seen in magnetic resonance images. STUDY DESIGN: Descriptive anatomical study. METHODS: Sixteen asymptomatic professional baseball players with no history of injury underwent bilateral elbow magnetic resonance imaging using a standardized sequencing protocol. The magnetic resonance images were reviewed, in a blinded fashion, by 2 musculoskeletal radiologists and 1 orthopaedic surgeon. RESULTS: Medial collateral ligament abnormalities (including thickening, signal heterogeneity, or discontinuity) were present in 87% of players' dominant elbows. Findings consistent with posteromedial impingement were present in 13 of 16 subjects. There was a significant correlation between medial collateral ligament thickening and posteromedial subchondral sclerosis (P = .04). The throwing elbow was correctly identified in all 16 subjects. No significant correlation between magnetic resonance imaging findings and age could be detected. CONCLUSIONS: This study demonstrates a high rate of abnormal magnetic resonance imaging findings in asymptomatic throwers' elbows. These baseline findings must be considered when magnetic resonance imaging is being used as a factor in treatment decisions.

Adolescent↗

Quantitative assessment of glenohumeral translation in baseball players: a comparison of pitchers versus nonpitching athletes.

BACKGROUND: Objective data quantifying differences in glenohumeral range of motion in baseball pitchers versus position players are established. There is limited information objectively comparing glenohumeral laxity in this same population. HYPOTHESIS: Baseball pitchers have greater difference in side-to-side anteroposterior translation of their throwing shoulders compared with position players. STUDY DESIGN: Prospective cross-sectional study. METHODS: Cutaneous electromagnetic sensors quantified anteroposterior shoulder translation of college and professional baseball players. Range of motion was measured. RESULTS: Nineteen position players and 37 pitchers were studied. Pitchers had a significant increase in external rotation of the dominant arm as compared with the nondominant arm (P = .02); the difference was not significant in position players (P = .34). The mean range of motion for pitchers' dominant arm was 110 degrees external rotation to 68 degrees internal rotation, and it was 100 degrees external rotation to 85 degrees internal rotation for position players (P = .278). The mean anteroposterior translation in pitchers' dominant arm was 33.30 mm and 29.84 mm in the nondominant side (P = .0001). This difference was not present in position players (P = .88). One of 19 position players had a side-to-side shoulder translation difference greater than 3 mm, compared with 22 of 37 pitchers (P = .0001). CONCLUSIONS: Pitchers have a greater amount of glenohumeral translation in the dominant arm. This difference is not seen in position players. These differences make the side-to-side comparison less useful in pitchers and should be considered when making therapeutic decisions.

Adolescent↗

Biomechanics of the shoulder in youth baseball pitchers: implications for the development of proximal humeral epiphysiolysis and humeral retrotorsion.

BACKGROUND: The effects of repetitive throwing on the shoulders of developing athletes are not well understood because of the paucity of data describing the biomechanics of youth pitchers and the plasticity of the developing skeleton. HYPOTHESIS: The direction and magnitude of the stresses that exist at the proximal humeral physis during the fastball pitching motion are consistent with the development of proximal humeral epiphysiolysis (Little League shoulder) and/or humeral retro-torsion. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 14 elite youth baseball pitchers (mean age, 12.1 +/- 0.4 years) were filmed from the front and dominant side while throwing fastballs in a simulated game. The net force and torque acting on the humerus throughout the throwing motion were calculated using standard biomechanical techniques. RESULTS: The external rotation torque about the long axis of the humerus reached a peak value of 17.7 +/- 3.5 N.m (2.7% +/- 0.3% body weight x height) just before maximum shoulder external rotation. A shoulder distraction force of 214.7 +/- 47.2 N (49.8% +/- 8.3% body weight) occurred at, or just after, ball release. CONCLUSION: Shear stress arising from the high torque late in the arm-cocking phase is large enough to lead to deformation of the weak proximal humeral epiphyseal cartilage, causing either humeral retrotorsion or proximal humeral epiphysiolysis over time. The stresses generated by the external rotation torque are much greater than those caused by distraction forces generated during the pitching motion of youth baseball pitchers. CLINICAL RELEVANCE: The motion of throwing fastballs by youth baseball pitchers results in force components consistent with proposed mechanisms for 2 clinical entities.

Baseball↗

Elbow range of motion in professional baseball pitchers.

BACKGROUND: Physicians involved with the care of baseball players have noted elbow range of motion changes in pitchers. Objective data regarding the extent of these changes have rarely been documented. HYPOTHESIS: Dominant and nondominant elbow range of motion differences are common in baseball pitchers, and these differences are related to player age, amount and length of time professionally pitched, and history of surgical procedures on the dominant extremity. STUDY DESIGN: Cross-sectional study; Level of evidence, 4. METHODS: Thirty-three professional pitchers were evaluated for elbow range of motion during spring training preseason physical examination. Dominant and nondominant elbow range of motion including flexion, extension, supination, and pronation were measured with a goniometer. Range of motion measures from the dominant and nondominant sides were compared. Baseball records were reviewed for arm dominance, age, years of professional pitching, professional innings pitched, and history of elbow surgery. These factors were evaluated for their possible association with range of motion for each side and the difference between sides. RESULTS: Statistically significant differences between dominant and nondominant sides were noted for elbow extension (dominant decreased 7.9 degrees +/- 7.4 degrees, P < .0001), flexion (dominant decreased 5.5 degrees +/- 7.8 degrees, P = .0003), and total flexion-extension arc (dominant decreased 13.3 degrees +/- 13.7 degrees, P < .0001). No significant difference between sides was found for the supination or pronation measures. No correlation was noted for age, pitching history, surgery, or arm dominance and the motion differences. CONCLUSION: Professional pitchers demonstrate elbow flexion and extension differences between dominant and nondominant elbows. No correlation was found between motion differences and age, pitching history, surgery, or arm dominance.

Adult↗

Ulnar nerve entrapment syndrome in baseball players.

Ulnar nerve entrapment at the elbow has been described in the literature. This paper deals with 19 skeletally mature baseball players with ulnar nerve entrapment who underwent surgery for correction of the problem. The surgery consisted of anterior transfer of the nerve and placement deep to the flexor muscles. Six players quit baseball because of continuing elbow problems, nine returned to playing, and four were lost to follow-up. Ulnar nerve entrapment is thought to represent one syndrome in a spectrum of diseases involving the medial side of the elbow in baseball players. The lesion is amenable to surgery.

Adolescent↗

The strength characteristics of internal and external rotator muscles in professional baseball pitchers.

The purpose of this study was to establish a data base regarding the isokinetic muscular performance characteristics of the external/internal rotator muscles of professional baseball pitchers. One hundred fifty healthy professional baseball pitchers were evaluated by use of a Biodex isokinetic dynamometer. The subjects tested had a mean age of 23.4 years and a mean body weight of 199 pounds. Isokinetic tests were performed concentrically at 180 and 300 deg/sec for both the throwing and nonthrowing shoulders. Testing procedures regarding positioning and stabilization followed established guidelines. The testing protocol and actual test repetitions were standardized for each subject. Statistical analysis was performed using the Pearson Product Moment Correlation and paired t-tests. Determination of the correlation coefficient was made at the P < 0.05 level of significance. Test results for bilateral comparison of mean peak torque for the throwing and nonthrowing shoulders indicated no statistically significant difference between the internal rotators at both test speeds, or for the external rotators at 300 deg/sec. There was a significant statistical difference at the 180 deg/sec test speed for the external rotators. The external/internal rotator strength ratio indicated a 65% ratio at 180 deg/sec and a 61% ratio at 300 deg/sec. Data were also collected for mean peak torque/body weight ratios of the throwing shoulder to establish a data base in professional throwers. This study offers clinical relevance in establishing a muscle performance profile for the professional thrower. This data base can therefore be used as criteria that should be met before an injured pitcher can be returned to throwing at the professional baseball level.

Adolescent↗

An eccentric- and concentric-strength profile of shoulder external and internal rotator muscles in professional baseball pitchers.

The purpose of this study was to establish a data base on the isokinetic eccentric muscular performance characteristics of external and internal rotator muscles in the shoulders of professional baseball pitchers. Concentric data are also included and compared with previously published concentric studies. Twenty-five professional baseball pitchers were evaluated with a Kin-Com isokinetic dynamometer. The subjects tested had a mean age of 23.5 years and a mean body weight of 199 pounds. Eccentric and concentric isokinetic tests were performed at 60 and 120 deg/sec. The testing protocol was standardized for each subject. Test results indicated no statistically significant difference in mean torque between throwing and nonthrowing shoulders for either external or internal rotator muscle groups. Eccentric strength was significantly greater than concentric strength for all muscle groups tested. The external-to-internal rotator muscle strength ratios were well above those previously published for high school through professional pitchers. Mean torque-to-lean body weight ratios were also included to establish a data base. This study establishes one of the first data bases for eccentric isokinetic muscle strength of shoulder rotator muscles in professional baseball pitchers. The data may help clinicians prevent and rehabilitate shoulder injuries in professional throwing athletes.

Adult↗

Glenohumeral range of motion and stiffness in professional baseball pitchers.

PURPOSE: This study was conducted to perform kinematic measures in a group of asymptomatic professional baseball pitchers to determine side-to-side differences in passive glenohumeral range of motion (ROM) and stiffness. We hypothesized that the throwing shoulder in asymptomatic pitchers would display greater passive glenohumeral stiffness than the contralateral nonthrowing shoulder. METHODS: Thirty-four professional baseball pitchers had bilateral assessments for passive glenohumeral ROM and stiffness during a single test session. ROM and stiffness measures were obtained objectively using standard goniometry and instrumented stress arthrometry, respectively. RESULTS: The throwing shoulder had significantly less (-8.5 degrees) internal rotation and significantly more external rotation (5.1 degrees) than the nonthrowing shoulder (P < 0.01). Passive joint stiffness was not significantly different between the throwing and nonthrowing shoulder, and anterior joint stiffness was significantly greater than posterior joint stiffness for both shoulders (P < 0.05). CONCLUSIONS: The repetitive stress of long-term throwing creates altered glenohumeral rotational patterns in the throwing shoulder of the professional baseball pitcher without compromising the joint's passive restraining quality.

Adult↗