Performance Of Baseball Players Research Articles

안쪽곁인대 불안정성이 야구선수들의 그립관련 근력 및 경기력에 미치는 영향

이 연구는 야구선수들을 대상으로 안쪽곁인대 불안정성이 그립관련 근력 및 경기력에 미치는 영향을 알아보고자 실시되었다. 대학교 야구선수 총 67명을 대상으로 실시하였으며, 안쪽곁인대 통증, 손상경력 및 불안정성 검사를 통하여 정상집단과 안쪽곁인대 불안정성집단으로 구분하였다. 신체적 특성, 통증 유무, 경기관련 요인(경기 불안감 및 투구 속도)을 측정한 결과는 다음과 같다. 안쪽곁인대 불안정성에 따른 신체적 특성은 유의한 차이가 나타나지 않았으며, 안쪽곁인대 불안정성을 가진 집단의 통증은 정상집단에 비하여 유의하게 높게 나타났다(p.001). 그립관련 근력은 팔꿈치 폄력과 악력이 유의한 차이를 나타냈으며, 안쪽곁인대 불안정성을 가진 집단이 정상집단에 비하여 유의하게 낮게 나타났다. 경기관련 요인 중 투구 속도가 유의한 차이를 나타냈으며, 안쪽곁인대 불안정성을 가진 집단이 정상집단에 비하여 유의하게 낮게 나타났다. 안쪽곁인대 불안정성은 통증유무와 유의한 양의 관련성(p.001)을 나타내고, 투구 속도와 유의한 음의 관련성(p.05)을 나타냈다. 통증 유무는 팔꿈치 폄력(p.001) 및 악력(p.05)과 유의한 음의 관련성을 나타냈다. 팔꿈치 굽힘력은 손목 굽힘/폄력(p.01) 및 악력(p.001)과 유의한 양의 관련성을 나타내고, 경기 불안감과 유의한 음의 관련성을 나타냈다(p.05). 손목 굽힘력은 손목 폄력 및 악력과 유의한 양의 관련성을 나타냈고(p.001), 악력은 투구 속도와 유의한 양의 관련성을 나타냈다(p.05). 이상의 결과를 요약해보면, 안쪽곁인대 불안정성과 악력은 투구 속도에 영향을 주는 것으로 나타났으므로 안쪽곁인대 불안정성을 예방하고 관리하면서 그립관련 근력을 증가시킬 수 있는 훈련 프로그램이 필요할 것으로 생각된다.

Warming Up With a Dynamic Moment of Inertia Bat Can Increase Bat Swing Speed in Competitive Baseball Players.

While most baseball players' warm-up with a weighted bat/donut, there is evidence to suggest the swing speed decreases after the warm-up even though the bat feels lighter. Warming up with a dynamic moment of inertia bat may not decrease the swing speed and therefore improve the performance of baseball players. The hypothesis is that a dynamic moment of inertia bat will negate the effect of the kinesthetic illusion observed with a weighted bat. To measure the difference in bat swing speed between warming up with the dynamic moment of inertia bat compared with a weighted bat. Thirty-nine competitive baseball players participated in the study. All players were randomly assigned a warm-up tool that could be either a dynamic moment of inertia bat or a weighted bat. After the players' warm-up, they swung their normal bat, and the bat swing speed was measured using a high-speed camera. We used motion analysis software to calculate the swing speed which measured the linear displacement during the last 15 frames before ball contact. The process was then repeated so that each player had the chance to try both warm-up bats. The post warm-up swing speeds using the dynamic moment of inertia bat were significantly faster compared with a weighted bat warm-up. There was a 0.56 (0.78)m/s (1.26 [1.74]mph) increase in swing speed when using the dynamic moment of inertia bat (P = .0001), which is an average increase of 2.10% compared with a weighted bat warm-up. Our findings suggest that using a dynamic moment of inertia bat before an at-bat can increase swing speed compared with a weighted warm-up. Future studies are needed to determine if using a dynamic moment of inertia bat as part of rehabilitation can facilitate returning to competition after injury by focusing on swing speed.

Acute Effects of Nicotine on Physiological Responses and Sport Performance in Healthy Baseball Players.

There is interest in whether nicotine could enhance attention in sporting performance, but evidence on the acute effect of nicotine on physical response and sports performance in baseball players remains scant. This was an observational study to examine whether nicotine gum chewed before exercise could provide acute effects on physiological responses and sport performance. Accordingly, heart rate variability (HRV), saliva cotinine concentration and α-amylase activity, cognitive function, muscle strength, and baseball-hitting performance were measured. Thirteen healthy male non-smoker baseball players were recruited. Conducting two sequences with 7-day intervals, they chewed nicotine gum (nicotine group) or flavor-matched placebo gum (placebo group) for 30 min. HRV and saliva analyses were conducted before gum consumption (S1), after gum consumption (S2), and after test completion (S3). Cognitive, muscle strength, and baseball-hitting performance tests were performed after nicotine or placebo gum chewing. The outcomes of all assessed variables were compared within and between the groups. Significant changes in HRV, α-amylase, testosterone, and cortisol were observed in the nicotine group at S2 and S3 (p < 0.05). Compared with the placebo group, the nicotine group exhibited enhanced motor reaction times, grooved pegboard test (GPT) results on cognitive function, and baseball-hitting performance, and small effect sizes were noted (d = 0.47, 0.46 and 0.41, respectively). Nicotine could induce changes in endocrine and sympathetic nerve activity and enhance cognitive function and baseball-hitting performance. However, no increase in muscle strength was observed after nicotine intake.

Hypermobility of ulnar nerve does not affect throwing performance (122)

Objectives:Ulnar nerve neuropathy around the elbow is a common pathology in throwing athletes, and occurs due to many factors including valgus elbow, and ulnar nerve hypermobility. For patients with ulnar nerve neuropathy, anterior transposition of the ulnar nerve is common procedures. Meanwhile, Ulnar nerve hypermobility has been reported to be present in 2% to 47% of asymptomatic individuals. However, no studies have investigated the rate of ulnar nerve hypermobility in throwing athletes, and the relationship between ulnar nerve mobility, and clinical symptom and throwing performance. This study was designed to classify the sonographic assessment for the mobility of the ulnar nerve compared to physical evaluation, and to determine whether ulnar nerve hypermobility is associated with clinical symptoms and throwing performance in baseball players. We investigated ulnar nerve hypermobility using ultrasound to evaluate the relationship between the ulnar nerve hypermobility and clinical sign including throwing performance in college baseball players.Methods:138 elbows in 69 college baseball players were examined. Each participant was queried regarding symptoms attributable to the ulnar nerve. In addition, structural measurements consisting of the tinel test and elbow flexion compression testing were examined. Sonographic examiners were, unaware of reported symptoms, independently performed a standardized examination of both elbows to assess ulnar nerve hypermobility. For sonographic assessment, the ultrasound probe was located at the medial condyle of the humerus to visualize the ulnar nerve in short-axis view in the extended elbow position. During extension to flexion of the elbow, the mobility of ulnar nerves was assessed, and categorized as stable, or hypermobile, which was further subclassified as subluxation, or dislocation (Figure 1A, 1B, 1C). Pared t-test was used to compare the mobility of the ulnar nerve between throwing and non-throwing sides. Fisher’s exact test was used to assess the relationship between physical exams and the mobility of the ulnar nerve. Values of p<0.05 were considered statistically significant.Results:Ulnar nerve hypermobility was identified in 54 (78.3%) of the 69 elbows in throwing side. Meanwhile, hypermobility was 53 (76.8%) in non-throwing side without significant difference, compared to non-throwing side. Elbows with nerve hypermobility did not experience a higher prevalence of subjective symptoms (snapping, pain, and tingling) than did elbows with stable nerves. Provocative physical examination testing for ulnar nerve irritability, however, showed consistent trends toward heightened irritability in hypermobile nerves (p = 0.04 to 0.16). Demographic data and anatomic measurements were similar between the subjects with stable nerves and those with hypermobile nerves. Additionally, all participants did not show decrease of throwing performance.Conclusions:Ulnar nerve hypermobility occurs in over half of the baseball players in throwing and non-throwing sides. Utilizing a standardized sonographic examination, a diagnosis of ulnar nerve hypermobility can be established with substantial interobserver reliability. In baseball players, ulnar nerve hypermobility does not appear to be associated with an increased symptomatology attributable to the ulnar nerve and throwing performance. Anterior transplantation of ulnar nerve may not be needed for baseball players with ulnar nerve neuropathy.

Lower Extremity Biomechanics Predicts Major League Baseball Player Performance.

Background:Although lower extremity biomechanics has been correlated with traditional metrics among baseball players, its association with advanced statistical metrics has not been evaluated.Purpose:To establish normative biomechanical parameters during the countermovement jump (CMJ) among Major League Baseball (MLB) players and evaluate the relationship between CMJ-developed algorithms and advanced statistical metrics.Study Design:Cohort study; Level of evidence, 3.Methods:MLB players in 2 professional organizations performed the CMJ at the beginning of each baseball season from 2013 to 2017. We collected ground-reaction force data including the eccentric rate of force development (“load”), concentric vertical force (“explode”), and concentric vertical impulse (“drive”) as well as the Sparta Score. The advanced statistical metrics from each baseball season (eg, fielding independent pitching [FIP], weighted stolen base runs [wSB], and weighted on-base average) were also gathered for the study participants. The minimal detectable change (MDC) was calculated for each CMJ variable to establish normative parameters. Pearson coefficient analysis and regression trees were used to evaluate associations between CMJ data and advanced statistical metrics for the players.Results:A total of 151 pitchers and 138 batters were included in the final analysis. The MDC for “load,” “explode,” “drive,” and the Sparta Score was 10.3, 8.1, 8.7, and 4.6, respectively, and all demonstrated good reliability (intraclass correlation coefficient > 0.75). There was a weak but statistically significant correlation between the Sparta Score and wSB (r = 0.23; P = .007); however, there were no significant correlations with any other advanced metrics. Regression trees demonstrated superior FIP with higher Sparta Scores in older pitchers compared with younger pitchers.Conclusion:There was a positive but weak correlation between the Sparta Score and base-stealing performance among professional baseball players. Additionally, older pitchers with a higher Sparta Score had statistically superior FIP compared with younger pitchers with a similar Sparta Score after adjusting for age.

Visuomotor predictors of batting performance in baseball players.

Hitting a baseball, one of the most difficult skills in all of sports, requires complex hand-eye coordination, but its link with basic visuomotor capabilities remains largely unknown. Here we examined basic visuomotor skills of baseball players and demographically matched nonathletes by measuring their ocular-tracking and manual-control performance. We further investigated how these two capabilities relate to batting performance in baseball players. Compared to nonathletes, baseball players showed better ocular-tracking and manual-control capabilities, which remain unchanged with increasing baseball experience. Both, however, become more correlated with batting accuracy with increasing experience. Ocular-tracking performance is predictive of batting skill, accounting for ≥ 70% of the variance in batting performance across players with ≥ 10 years of experience. A simple linear additive-noise cascade model with shared front-end visual noise that limits batting performance can explain many of our results. Our findings show that fundamental visuomotor capabilities can predict the complex, learned skill of baseball batting.

No change in performance metrics in major league baseball players sustaining wrist fractures after being struck by an errant pitch

ObjectiveThis study aimed to determine the effect of wrist fractures on performance metrics in Major League Baseball Players after they were hit by an errant pitch. MethodsPlayers who sustained wrist fractures after being struck by a pitch were identified and changes in performance metrics were calculated. ResultsIn both the short- and medium-term analysis, there were no significant differences in all pre- and post-injury offensive statistics following return to play. ConclusionWrist fractures sustained after being struck by an errant pitch do not significantly impact professional baseball player performance if the player is able to return to sport.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters

BACKGROUND CONTEXT Major League Baseball (MLB) players are at significant risk for back injury, and back injury accounts for a significant proportion of time spent on the disabled list. MLB players that sustain back injuries are either managed conservatively or undergo operation with the goal of returning to their full level of pre-injury performance. Performance data of MLB players is a readily available method of objectively comparing performance outcomes following recovery from back inury. PURPOSE To better understand differences in performance outcomes and ability to return to play following back injury in MLB players. STUDY DESIGN/SETTING This is a retrospective cohort study comparing performance outcomes in MLB players with back injury who underwent conservative versus surgical managment. PATIENT SAMPLE Major League Baseball players that sustained a documented back injury between 2010 and 2016 as recorded in individual MLB team disabled lists. Inclusion criteria also required that players have statistical performance data available one year prior to the injury and following return to play. OUTCOME MEASURES Various outcome measures of in-game performance were measured using hitting and pitching metrics. Hitting performance was assessed using at bats, hits, batting average, home runs, RBIs, and OPS. Pitching performance was analyzed using win/loss ratio, ERA, saves, innings pitches, strike outs and WHIP. Fast ball velocity and pitch selection was also analyzed. Time on the disabled list and whether players returned to play were determined. METHODS Players who sustained back injury were identified using publically available disabled listings from MLB teams from 2011 to 2016. Conservative versus surgical treatment method was determined by using news media and team-affiliated reporting on injured players. Online statistical data on MLB players performance metrics and pitch selection was gathered for the players meeting inclusion criteria. Performance data was compared from one year prior to the injury to one year following return to play to assess change in performance. RESULTS A total of 187 players were identified who sustained back injury between 2010 and 2016. Of these, data was analyzed from 126 players who met inclusion criteria. A total of 100 and 26 players were treated with conservative and surgical management, respectively. The average age was 33. Surgeries included thoracic and lumbar fusion, and discectomy or microdiscectomy of the lumbar and cervical spine. Players undergoing surgery averaged significantly longer time on the disabled list (126days and 41days, respectively). Pitcher earned run average was increased more in the conservative treatment group than the surgical treatment group (increases of 1.15 and 0.4, respectively). Pitcher fastball velocity decreased and frequency of curveball and change-up pitch selection increased. Players undergoing operative management were less likely to return to play. CONCLUSIONS Major league baseball player performance declines following back injury regardless of the form of treatment. Players undergoing surgery miss more playing time and are less likely to return to play than those undergoing conservative therapy. However, when indicated, surgery may be beneficial in maintaining pitching performance as opposed to conservative management.

The contract year syndrome in the NBA and MLB: A classic undermining pattern

We assembled National Basketball Association and Major League Baseball player performance data from recent years, tracking 3 year periods in players’ careers: pre-contract year (baseline), contract year (CY; salient external incentive present), and post-contract year (salient external incentive removed). In both sports, we examined both individual scoring statistics (points scored, batting average) and non-scoring statistics (e.g. blocked shots, fielding percentage) over the 3 years. Using extrinsic motivation theories, we predicted and found a boost in some scoring statistics during the CY (relative to the pre-CY), but no change in non-scoring statistics. Using intrinsic motivation theories, we predicted and found an undermining of many statistics in the post-CY, relative to both the CY and the pre-CY baseline. Boosted CY scoring performance predicted post-CY salary raises in both sports, but salary raises were largely unrelated to post-CY performance. The CY performance boost is real, but team managers should know that it might be followed by a performance crash—the CY “syndrome.”

Reassessing the association between facial structure and baseball performance: a comment on Tsujimura &amp; Banissy (2013)

Are the associations between the facial width-to-height ratio (fWHR) and Japanese male baseball player performance documented by Tsujimura & Banissy [[1][1]] robust to controlling for body mass index (BMI)? Two factors motivate this question. First, research suggests that BMI is positively

The immediate effect of lumbar spine patterns of neuromuscular joint facilitation in young amateur baseball players.

[Purpose] The aim of the study was to investigate the changes in baseball pitching velocity, the functional reach test (FR) and the simple reaction times (SRT) in young amateur baseball players after lumbar spine patterns of neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 11 young amateur baseball players. An NJF intervention and a proprioceptive neuromuscular facilitation (PNF) intervention were performed. The interventions were performed one after the other with one week between them. The order of the interventions was completely randomized. [Methods] The baseball pitching velocity, the FR and the SRT were evaluated before and after treatment. [Results] In the NJF group, there were significant differences in baseball pitching velocity, FR and SRT after treatment. In the PNF group, there was a significant difference in SRT after treatment. [Conclusion] NJF intervention shortens the SRT, increases the baseball pitching velocity and FR, and may be recommended to improve performance in baseball players.

A study of static, kinetic, and dynamic visual acuity in 102 Japanese professional baseball players

BackgroundIt seemed that visual functions might have some effects on the performance of baseball players. We measured static, kinetic, and dynamic visual acuity (SVA, KVA, and DVA, respectively) of Japanese professional baseball players to ascertain whether there would be any difference in SVA, KVA, and DVA among player groups stratified according to their performance level.MethodsThe subjects were 102 male professional baseball players with a mean age of 26 years who were members of a Japanese professional baseball club from 2000 to 2009. They were stratified into three groups according to their performance level: A (players who were on the roster of the top-level team all the time throughout the study period), B (players who were on the roster of the top-level team sometimes but not all the time), and C (players who were never on the roster of the top-level team). They were interviewed for the use of corrective visual aids, and examined for SVA, KVA, and DVA. The measurements of these parameters were compared among groups A, B, and C. We also investigated and analyzed the association of KVA or DVA with player position (pitchers or fielders) and with hand dominance for batting. KVA was compared between the pitchers and the fielders because they each require different playing skills. DVA was compared between the right-handed and the left-handed batters.ResultsThere was no statistically significant difference among groups A, B, and C. There was a statistically significant difference in KVA between the pitchers and the fielders (t-test; P < 0.05) There was no statistically significant difference in DVA between the right-handed and the left-handed batters.ConclusionsThere was no significant difference in the examined visual functions among player groups with different performance levels.

Effects of neuromuscular joint facilitation on baseball pitching velocity and electromechanical reaction times of the teres major of young amateur baseball players.

[Purpose] The aim of this study was to investigate the changes of baseball pitching velocity and electromechanical reaction times (EMG-RT) of the teres major of young amateur baseball players after neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 18 healthy males who were divided into two groups: a NJF group and a control group. The NJF group consisted of 10 subjects, and the control group consisted of 8 subjects. [Methods] Participants in the NJF group received NJF treatment. The baseball pitching velocity, the EMG-RT, the premotor time (PMT), and the motor time (MT) during shoulder internal rotation movement were measured before and after 8 weeks of exercise. [Results] There were no significant differences among the results of the control group. In the NJF group, there were significant differences in baseball pitching velocity, EMG-RT and MT after NJF treatment. [Conclusion] NJF intervention shortens not only EMG-RT but also MT, which implies that NJF is effective for motor processes. Since the baseball pitching velocity increased, NJF may be recommended for the improvement of the performance of baseball players.

Perspectives of Training Using the Game Broadcasting in High School Baseball Players

Practical demonstration is one of the most often used tools to facilitate motor skill learning. The purpose of this study was to investigate the perspectives of training using the game broadcastings in high school baseball players in Taiwan. In this study, baseball ability was categorized into five types: Pitching, batting, fielding, tactics, and knowledge of baseball. The questionnaires were distributed to the players and coaches of the 2010 Da-Tong PX Cup. Descriptive statistics, independent t-test, and one-way ANOVA were adopted for data analysis. The results were indicated as followed: (1) Coaches and players agreed that game broadcasting was helpful for baseball ability learning. However, the level of agreement between pitching and tactics has shown a significant different (p＜.05); (2) The players, who were already used video as a means of training tended to agree that broadcasting can foster baseball skill learning. It was suggested that further research is needed to examine the effect of using broadcasting as a training method on the motivation and performance in baseball players.

One-Hit Wonders: A Study of Contract-Year Performance among Impending Free Agents in Major League Baseball

INTRODUCTION In 2004, Adrian Beltre, then a twenty-five-year-old third baseman for the Los Angeles Dodgers, entered the final year of his first major-league contract. That year, Beltre posted the best statistics of his career. He finished the year with career highs in hits, home runs, runs batted in (RBI), batting average, on-base percentage (OBP), and slugging percentage (SLG). (1) He parlayed this performance into a major with the Seattle Mariners through free agency, increasing his salary by over loo percent. Unfortunately for the Mariners, Beltre did not come close to producing at the level he did during his year. For example, in 2004 Beltre hit 48 home runs and had a batting average of .334; after signing his new with Seattle, his season high in home runs was 26 and his season high batting average was .276. (2) Beltre seemed to have a resurgence with the Boston Red Sox in 2010, but nevertheless, in baseball circles, cases like Adrian Belire's evoke the idea of the contract-year phenomenon. As described by author Malcolm Gladwell, the contract-year phenomenon is a theory that asserts that players--regardless of their sport--will statistically perform better in the final year of their than they have in previous years, in an effort to receive larger contracts on the free-agent market. (3) The phenomenon is so ingrained in modern baseball culture that ESPN.com produced an entire article for fantasy baseball enthusiasts, profiling players in years who should perform well based entirely on this theory. (4) In the high stakes world of Major League Baseball (MLB), where contracts have reached remarkable figures, management needs a way to properly evaluate and compensate a free-agent player. If this contract-year phenomenon exists, and general managers act on short-term performance, they will not likely get what they pay for. The literature on baseball player performance has approached the issue from several different perspectives. PLAYER MEASUREMENT AND COMPENSATION A great difficulty exists in determining a player's monetary value in professional baseball. Statistics provide quantitative data to use in comparison to other contemporary and historical players. However, management must then decide which statistics are important and deserve more value than others. Is a home run more valuable than a stolen base? If management places value on certain statistics when evaluating a player, they are providing incentives for that player to behave opportunistically. Holbrook and Shultz examined the salary model in MLB. They wanted an answer to the question How much is a home run worth? The authors designed a formula to determine the effects a player's statistical performance had on future enhancement or diminishment of value. (5) Their study effectively assigned a dollar amount to every hit, home run, fielding error, etc. Although the contract-year phenomenon was not the focus of their study, they did find that in a player's year, home runs became more valuable while hits became less valuable. Reaching the stage of potential free agency did cause changes in the value of statistics relative to the ultimate payoff the player received based on that performance. This study demonstrated that pay and performance are highly correlated, especially in a player's free-agent year. Therefore, players realize the incentive of parlaying a great statistical season into a large payday through free agency. Lackritz, in his study of salary evaluation for MLB players, concluded that the only proper way to compensate a player was on a yearly commission basis. He argued that a player's value should be determined based on individual and team performance and pay could vary greatly from year to year. (6) This would reduce the financial risk for teams and deter opportunistic behavior on the part of the athletes. Every year would be a contract year. …

The effects of taping on scapular kinematics and muscle performance in baseball players with shoulder impingement syndrome

Purpose This study aimed to investigate the effect of elastic taping on kinematics, muscle activity and strength of the scapular region in baseball players with shoulder impingement. Scope Seventeen baseball players with shoulder impingement were recruited from three amateur baseball teams. All subjects received both the elastic taping (Kinesio Tex TM) and the placebo taping (3 M Micropore tape) over the lower trapezius muscle. We measured the 3-dimensional scapular motion, electromyographic (EMG) activities of the upper and lower trapezius, and the serratus anterior muscles during arm elevation. Strength of the lower trapezius was tested prior to and after each taping application. The results of the analyses of variance (ANOVA) with repeated measures showed that the elastic taping significantly increased the scapular posterior tilt at 30° and 60° during arm raising and increased the lower trapezius muscle activity in the 60–30° arm lowering phase ( p < 0.05) in comparison to the placebo taping. Conclusions The elastic taping resulted in positive changes in scapular motion and muscle performance. The results supported its use as a treatment aid in managing shoulder impingement problems.

Effects of stimulus–response compatibility in mediating expert performance in baseball players

The purpose of this study was to examine whether the baseball players' shorter Go/Nogo reaction time (RT) was influenced by stimulus–response compatibility (SRC) effects. To accomplish this purpose, we examined RTs and event-related potential components in three Go/Nogo tasks, manipulating stimulus–response relations. The participants were nine college baseball players (Baseball) and nine college non-baseball players (Control). Task conditions were the following: spatial condition with baseball batting-specific S–R mapping (Spatial-BB) demands response execution or inhibition corresponding to spatial stimulus location. This condition was similar to the stimulus–response relations in baseball batting. The other two tasks demand their response based on the stimulus location or colors. These tasks did not have any baseball-specific stimulus–response relations. As a result of RTs, baseball players revealed shorter RTs in Spatial-BB than other tasks, but the control group showed similar RTs among three tasks. In Go trials, as for the interval between stimulus and lateralized readiness potential (LRP) onset which is the duration to the end of response selection, baseball players had shorter than control in Spatial-BB, whereas P300 latency and the interval between LRP and response did not show any difference between groups or among tasks. In Nogo trials, the augmented P300 amplitude of baseball players at frontal (Fz) was observed in Spatial-BB. The P300 amplitude in Nogo trials is often interpreted as the strength of inhibition. These results indicated that the facilitation of RTs in baseball players is likely due to a faster response selection and stronger inhibition caused by SRC effects in relation to specific S–R mapping.

Interactions between Workers and the Technology of Production: Evidence from Professional Baseball

This paper examines how the effort choices of workers within the same firm interact with each other. In contrast to the existing literature, we show that workers can affect the productivity of their co-workers based on income maximization considerations, rather than relying on behavioral considerations such as peer pressure, social norms, and shame. Theoretically, we show that a worker’s effort has a positive effect on the effort of co-workers if they are complements in production, and a negative effect if they are substitutes. The theory is tested using panel data on the performance of baseball players from 1970 to 2003. The empirical analysis shows that a player’s batting average significantly increases with the batting performance of his peers, but decreases with the quality of the team’s pitching. Furthermore, a pitcher’s performance increases with the pitching quality of his teammates, but is unaffected by the batting output of the team. These results are inconsistent with behavioral explanations which predict that shirking by any kind of worker will increase shirking by all fellow workers. The results are consistent with the idea that the effort choices of workers interact in ways that are dependent on the technology of production. These findings are robust to controlling for individual fixed-effects, and to using changes in the composition of one’s co-workers in order to produce exogenous variation in the performance of one’s peers.

Interactions between Workers and the Technology of Production: Evidence from Professional Baseball

This paper examines how the effort choices of workers within the same firm interact with each other. In contrast to the existing literature, we show that workers can affect the productivity of their co-workers based on income maximization considerations, rather than relying on behavioral considerations such as peer pressure, social norms, and shame. Theoretically, we show that a worker's effort has a positive effect on the effort of co-workers if they are complements in production, and a negative effect if they are substitutes. The theory is tested using panel data on the performance of baseball players from 1970 to 2003. The empirical analysis shows that a player's batting average significantly increases with the batting performance of his peers, but decreases with the quality of the team's pitching. Furthermore, a pitcher's performance increases with the pitching quality of his teammates, but is unaffected by the batting output of the team. These results are inconsistent with behavioral explanations which predict that shirking by any kind of worker will increase shirking by all fellow workers. The results are consistent with the idea that the effort choices of workers interact in ways that are dependent on the technology of production. These findings are robust to controlling for individual fixed-effects, and to using changes in the composition of one's co-workers in order to produce exogenous variation in the performance of one's peers.

Comparing the Performance of Baseball Players

This article extends ideas from the economics literature on multiple output production and efficiency to develop methods for comparing baseball players that take into account the many dimensions to batting performance. A key part of this approach is the output aggregator. The weights in this output aggregator can be selected a priori (as is done with batting or slugging averages) or can be estimated statistically based on the performance of the best players in baseball. Once the output aggregator is obtained, an individual player can then be measured relative to the best, and a number between 0 and 1 characterizes his performance as a fraction of the best. The methods are applied to hitters using data from 1995–1999 on all regular players in baseball's major leagues.