Japanese Professional Baseball Research Articles

Fundamental study on ambient noise reduction for analysis of hitting sound of professional baseball players

In recent years, the sound of a hitting ball during a baseball game has focused attention on the American Major League Baseball and Japanese professional baseball. It is reported that information such as the direction and distance of a batted ball can be detected from the sound. The sounds of players hitting the ball are sometimes expressed using various onomatopoeic. In our previous study, we recorded the sound of a baseball hit during hitting practice for players of a university baseball team in the Tokyo metropolitan area in Japan. Relationships between the acoustic characteristics of the sound and the distance and direction of the ball were clarified. In this research, acoustic analysis of professional baseball players' batted ball sounds from Youtube and other videos is used to identify the acoustic features and characteristics of the batted ball. This paper describes the method and accuracy of noise removal around the hitting sound extracted from the video using a convolutional neural network with images.

Morphological Evaluation of Lumbar Facet Joints in Professional Baseball Players.

Many professional baseball players experience low back pain, a major cause of which is lumbar facet joint arthropathy. To evaluate the relationship between the dominant hand side and facet joint morphology in baseball movement. Cross-sectional study; Level of evidence, 3. Participants were 25 Japanese professional baseball players (11 pitchers and 14 fielders) with low back pain and lower limb symptoms. Player age, hand dominance, and length of professional playing experience were recorded, and the lateral diameter of all lumbar facet joints was determined from the axial computed tomography scans. We defined the facet joints ipsilateral and contralateral to the dominant hand as dominant and nondominant, respectively. The nondominant-to-dominant (N/D) ratio of the lateral diameter was calculated, and differences between the pitchers and fielders were analyzed using the unpaired t test. The average player age and length of professional playing experience were 26.9 years (range, 19-37 years) and 7.2 years (range, 1-15 years), respectively. The right hand was dominant in 9 pitchers and 5 fielders, while the left hand was dominant in 2 pitchers and 9 fielders. In pitchers, the average lateral facet joint diameter on the nondominant side was significantly larger than on the dominant side at all vertebral levels except L1 to L2 (P < .05 for all). The N/D ratio for each facet joint was 1.06 (L1-L2), 1.11 (L2-L3), 1.10 (L3-L4), 1.12 (L4-L5), and 1.12 (L5-S1). In fielders, the average lateral facet joint diameter on the dominant side was significantly larger than on the nondominant side at L3 to L4 (P < .05), with N/D ratios of 0.98 (L1-L2), 0.96 (L2-L3), 0.94 (L3-L4), 0.97 (L4-L5), and 0.98 (L5-S1). The N/D ratio was significantly larger in pitchers than in fielders at all levels (P < .05 for all). The facet joints of professional baseball players were enlarged asymmetrically, with different tendencies observed between pitchers and fielders. Although pitching and batting are movements that transmit the rotation from the lower limbs to the upper limbs, the effects of rotation and lateral flexion were associated significantly with facet joint hypertrophy.

Is Labor in Sport a Commodity? The Case of American and Japanese Professional Baseball

An important rule that underpins international and domestic labor law is the principle that labor is not a commodity. This principle has interesting application to the labor regulation in professional team sports such as baseball that utilize drafts, salary restraints, the reserve system, and free agency. The article will examine whether these and other labor controls in Major League Baseball in the United States and Nippon Professional Baseball League in Japan commodify labor. Baseball’s labor controls and practices will be assessed to determine if labor is treated as a commodity, and if so, whether there is undue commodification. In doing so, a construct will be created of labor practices that commodify labor on a spectrum. These labor practices and controls will also be evaluated in the context of antitrust law and restraint of trade. The article concludes by suggesting ways to improve the treatment of players that will decommodify labor.

Characteristics of subscapularis muscle strain in professional baseball players: a case series

Subscapularis muscle strains can develop in professional baseball players, rendering the players unable to continue playing for a certain period. However, the characteristics of this injury are not well known. The purpose of the present study was to investigate the details of the injury and the post injury course of subscapularis muscle strain in professional baseball players. Of 191 players (83 fielders and 108 pitchers) who were members of a single Japanese professional baseball team between January 2013 and December 2022, 8 players (4.2%) had subscapularis muscle strain and were enrolled in this study. The diagnosis of muscle strain was made on the basis of shoulder pain and magnetic resonance imaging findings. The incidence of subscapularis muscle strain, the details of the site of the injury, and the time to return to play were examined. Subscapularis muscle strain occurred in 3 (3.6%) of 83 fielders and 5 (4.6%) of 108 pitchers, with no significant difference between fielders and pitchers. All players had injuries on the dominant side. Most injuries were located at the myotendinous junction and in the inferior half of the subscapularis muscle. The mean time to return to play was 55.3±40.0 (range, 7-120) days. At a mean 22.7 months after the injury, there were no re-injured players. Baseball players who have shoulder pain should be regarded as having possible subscapularis muscle strain, and careful examination should be considered.

Feeling Vital by Watching Sport: The Roles of Team Identification and Stadium Attendance in Enhancing Subjective Vitality

Subjective vitality is an important, yet understudied, indicator of eudaimonic well-being. People experience subjective vitality when they engage in need-satisfying activities. We investigate two sport consumption activities (stadium attendance and sport television viewing), team identification, and subjective vitality to understand how sport consumption mediates the impact of team identification on subjective vitality. Throughout a season, data were collected from local residents (n = 618) living within the franchise area of a Japanese professional baseball team. Structural equation modeling and bootstrapping mediation analysis showed that team identification exerted both a direct and an indirect effect via attendance frequency on subjective vitality. The proposed model and the findings offer new theoretical insights into the roles of subjective vitality, team identification, and stadium attendance in spectator sport. Consequently, sport teams can leverage these insights to intensify consumer experiences when people attend games, positively contributing to their well-being.

Pitching strategy evaluation via stratified analysis using propensity score

Abstract Recent measurement technologies enable us to analyze baseball at higher levels of complexity. There are, however, still many unclear points around pitching strategy. There are two elements that make it difficult to measure the effect of a pitching strategy. First, most public datasets do not include location data where the catcher demands a ball, which is essential information to obtain the battery’s intent. Second, there are many confounders associated with pitching/batting results when evaluating pitching strategy. We here clarify the effect of pitching attempts to a specific location, e.g., inside or outside. We employ a causal inference framework called stratified analysis using a propensity score to evaluate the effects while removing the effect of confounding factors. We use a pitch-by-pitch dataset of Japanese professional baseball games held in 2014–2019, which includes location data where the catcher demands a ball. The results reveal that an outside pitching attempt is more effective than an inside one to minimize allowed run average. In addition, the stratified analysis shows that the outside pitching attempt is effective regardless of the magnitude of the estimated batter’s ability, and the proportion of pitched inside for pitcher/batter. Our analysis provides practical insights into selecting a pitching strategy to minimize allowed runs.

Why Elite Athletes Choose Teaching as a Second Career : Cases of Japanese Professional Baseball and Football Players

Why Elite Athletes Choose Teaching as a Second Career : Cases of Japanese Professional Baseball and Football Players

Mass Gathering Sport Events and the Spread of Viral Respiratory Infection: Japanese Professional Baseball and Influenza

Using weekly-level influenza case data from all 47 prefectures in Japan alongside data from Nippon Professional Baseball (NPB) league from 1999 to 2018, we examine the effect of hosting games on local influenza transmission. The results highlight that during the flu season, for every NPB game held at its home ballpark, there is an average increase of 0.18 cases per sentinel medical institution (SMI) between that week and the following week. The effects are robust to different specifications and placebo tests. This translates to about a 0.1% increase in the number of cases during the overlap of NPB and flu seasons.

Low Back Pain and Lumbar Degeneration in Japanese Professional Baseball Players.

Background:Baseball is one of the most popular sports in Asia. It is known that baseball can easily lead to back pain. However, there has been no survey of low back pain (LBP) and lumbar disc degeneration in Japanese professional baseball players to date.Purpose:To investigate the cause of LBP and lumbar degeneration in professional Japanese baseball players.Study Design:Cross-sectional study; Level of evidence, 3.Methods:We retrospectively reviewed the medical records of Japanese professional baseball players with LBP who visited our hospital. Data were collected from July 2018 to April 2021. We also investigated whether the results differed between players in their 20s and 30s or between pitchers and fielders. Data analysis was performed using the chi-square test.Results:We surveyed 32 professional baseball players. The most frequent causes of LBP among players in their 20s (n = 21) were lumbar disc herniation (LDH; 57%) and spondylolysis (24%). Of the players with spondylolysis, 50% had adult-onset spondylolysis. Players in their 30s (n = 11) most commonly had discogenic pain (55%) as well as LDH and facet joint arthritis (each 18%). The incidence of lumbar intervertebral disc degeneration was significantly higher in players in their 30s (91%) than those in their 20s (14%), as was the incidence of Schmorl nodes and Modic type 1 changes. There was no significant difference in the cause of LBP or the incidence of lumbar intervertebral disc degeneration between pitchers and fielders (P = .59).Conclusion:Among professional baseball players in their 20s, lumbar degeneration was less common, and they most frequently developed diseases less related to degeneration, such as LDH. However, among players in their 30s, lumbar degeneration was more advanced, and degenerative diseases such as discogenic pain occurred more frequently. Research on training methods could lead to the prevention of LBP. Our data may be applicable to other professional athletes and will contribute to diagnosis and treatment.

Characteristics of internal oblique muscle strain in professional baseball players: a case series

BackgroundInternal oblique muscle strains can develop in professional baseball players, rendering the players unable to continue playing for a certain period. However, the characteristics of this injury are not well known. The purpose of the present study was to investigate the details of the injury and the post injury course of internal oblique muscle strain in professional baseball players.MethodsThe subjects were members of a single Japanese professional baseball team with a total of 188 players (81 fielders and 107 pitchers) who developed internal oblique muscle strains from January 2012 to December 2021. The diagnosis of muscle strain was made on the basis of local pain and magnetic resonance imaging findings. The incidence of internal oblique muscle strain, the details of the site of the injury, and the time to return to play were examined.ResultsThere were 28 cases in 23 players (12.2%) of internal oblique muscle strain. The players were 16 fielders (24.7%) and 7 pitchers (7.5%), with a significantly greater incidence in fielders (p = 0.001). Although internal oblique muscle strain was more common on the side contralateral to the batting or pitching side, it occurred on either side. Most of the injury sites were at the region of the muscle insertion to the lower ribs. At a mean time of 36.5 months after the initial injury, 5 players (21.7%) developed another internal oblique muscle strain. The mean time to return to play was 27.7 ± 9.7 days (range, 4–53 days).ConclusionsBaseball players who have symptoms at the side of the trunk should be regarded as having possible internal oblique muscle strain, and proactive examination should be considered.

일본 프로야구팀의 비주얼 아이덴티티의 이미지 색채 적용에 관한 연구 - 엠블럼, 컬러, 마스코트를 중심으로

Professional baseball teams express their identities to the audience through the colors of their emblems and mascots. The emblem is a visual language that symbolizes a baseball team, making it easy to recognize by the audience as an abstract or conceptual image. The mascot is an identity element that audiences may prefer and are easily accessible. This study targets the top 5 teams in 2018 (10 teams) for each league among the teams in the two major leagues of Japanese professional baseball (Central League, Pacific League). This study intends to construct a visual identity by drawing differences in identity. Each baseball team

Muscle Strains in the Lower Extremity of Japanese Professional Baseball Players.

Background:Predicting when athletes can return to play after muscle strains is not always simple because of difficulties in evaluating the severity of such injuries.Purpose/Hypothesis:The purpose of this study was to evaluate the use of magnetic resonance imaging (MRI) to classify lower extremity muscle strains in Japanese professional baseball players. The hypothesis was that MRI grading can be used to diagnose the severity of muscle strains in the lower extremity and predict return to play in athletes.Study Design:Case series; Level of evidence, 4.Methods:A total of 55 muscle strains occurred in the lower extremity of players on a professional baseball team between the 2006 and 2015 seasons; all players had undergone MRI examination. Age, player position, location of injury, cause of injury, and duration until return to play (in days) were extracted from the medical records. MRI scans were classified using the following system: grade 0, no abnormal findings; grade 1a, T2-weighted high intensity only between muscles; grade 1b, T2-weighted high intensity between muscles and in muscle belly; grade 2, injury of musculotendinous junction; and grade 3, rupture of tendon insertion.Results:The sites of injuries were distributed as follows: hamstrings (n = 33), quadriceps (n = 6), hip adductors (n = 6), and calves (n = 10). MRI findings revealed 9 muscle strains (16%), 19 grade 1a (34%), 19 grade 1b (34%), and 8 grade 2 muscle strains (16%). The length of time until return to training and competition, respectively, was 15 and 26 days for grade 1a injuries, 19 and 36 days for grade 1b injuries, and 55 and 69 days for grade 2 injuries.Conclusion:Players with grade 1 injuries took 4 to 5 weeks to return to play, whereas players with grade 2 injuries took 10 weeks to return. MRI can be useful for diagnosing lower extremity muscle strains and predicting the time to return to play.

Ossification of the ligamentum flavum in the thoracic spine mimicking sciatica in a young baseball pitcher:a case report

Thoracic ossification of the ligamentum flavum (OLF) is a pathological condition that causes myelopathy, with unilateral lower extremity pain rarely a feature in the presenting complaint. Moreover, most symptomatic cases of thoracic OLF occur in middle-aged men, with younger individuals rarely affected. We present a rare case of severe and chronic unilateral buttock and leg pain mimicking sciatica due to thoracic OLF in a professional baseball pitcher. A 28-year-old, right-handed, Japanese professional baseball pitcher experienced intractable left leg pain with numbness and spasticity. After the initial presentation, extensive testing focusing on lumbar, hip, and pelvis lesions failed to identify a cause for the pain. One year after onset, careful neurological examination showed signs of upper motor neuron disturbance, and thoracic computed tomography and magnetic resonance imaging revealed thoracic OLF at the level of the thoracolumbar junction. After resection of the thoracic OLF, the pain, numbness, and spasticity completely resolved. He resumed full training and was pitching in top condition within four months after surgery. Though rare, thoracic OLF should be considered in the differential diagnosis of lower extremity pain in young athletes, especially amongst high-level baseball pitchers.

Features on throwing motion to the second base in Japanese professional baseball catchers

Features on throwing motion to the second base in Japanese professional baseball catchers

Relationship Between Physical Fitness at the End of Preseason and the Inseason Game Performance in Japanese Female Professional Baseball Players.

Watanabe, Y, Yamada, Y, Yoshida, T, Matsui, T, Seo, K, Azuma, Y, Hiramoto, M, Miura, Y, Fukushima, H, Shimazu, A, Eto, T, Saotome, H, Kida, N, and Morihara, T. Relationship between physical fitness at the end of preseason and the inseason game performance in Japanese female professional baseball players. J Strength Cond Res 33(6): 1580-1588, 2019-This study examined anthropometric and fitness profiles of Japanese female professional baseball players and investigated the relationship between players' physical fitness and inseason game performance. Fifty-seven players who were registered in the Japan Women's Baseball League (JWBL) participated. Height, body mass, grip strength, back strength, knee extension and flexion strength, hamstring extensibility, vertical jump height, and horizontal jump distance were measured at preseason (February and March) in 2013. Game performance during the 2013 season (March-November) was obtained from official JWBL statistics. Vertical jump height showed significant positive correlations with individual performance records (e.g., total bases [r = 0.551], slugging percentage [r = 0.459], and stolen bases [r = 0.442]). Similar relationships were observed between horizontal jump distance and performance statistics in most cases. By contrast, grip, back, and lower-limb strength, as well as hamstring extensibility were not significantly correlated with game performance. Stepwise regression analysis selected vertical jump height as an independent variable, significantly correlating with several game performance measures (e.g., total bases: adjusted R = 0.257). Also, vertical jump height and body mass index were identified as independent variables significantly associated with stolen bases (adjusted R = 0.251). Maximal jump performance, rather than simple isometric muscle strength or flexibility, is a good performance test that can be used at the end of preseason to predict inseason batting and stolen base performance. Our findings demonstrate the importance of constructing preseason training programs to enhance lower-limb muscular power that is linked to successful inseason performance in female baseball players.

Biomechanical Differences Between Japanese and American Professional Baseball Pitchers.

Background:Although baseball injuries are common in both Japan and the United States, the majority of pitching injuries in Japanese players occur at the shoulder, whereas most pitching injuries in American players occur at the elbow. A biomechanical comparison between Japanese and American pitchers may help to identify the different injury mechanisms.Hypothesis:Japanese pitchers produce greater shoulder kinetics whereas American pitchers generate greater elbow kinetics. Also, kinematic differences will be found between the 2 groups, including longer stride and greater lead knee flexion for Japanese pitchers.Study Design:Descriptive laboratory study.Methods:Biomechanical data for 19 Japanese professional baseball pitchers and an age-matched group of 19 American professional baseball pitchers were collected by use of a 3-dimensional, automated, high-speed optical motion capture system. Anthropometric, kinetic, and kinematic data for both groups were compared by use of t tests (P < .05).Results:American pitchers were taller and heavier and generated greater ball velocity (38.1 ± 1.6 vs 34.7 ± 1.1 m/s; P < .001) than their Japanese counterparts. Most elbow and shoulder kinetic parameters, including elbow varus torque (99 ± 17 vs 86 ± 17 N·m; P = .018), were greater for American pitchers. However, when normalized by bodyweight and height, shoulder horizontal adduction torque was greater for Japanese pitchers (6.8% ± 1.0% vs 5.8% ± 1.1%; P = .005). Japanese pitchers had longer stride (86% ± 5% vs 82% ± 6% of height; P = .023), greater shoulder abduction at ball release (101° ± 8° vs 94° ± 9°; P = .014), and greater knee flexion after ball release (39° ± 18° vs 28° ± 14°; P = .039). Japanese pitchers also demonstrated greater shoulder internal rotation velocity, elbow flexion, and elbow extension velocity.Conclusion:Greater elbow varus torque may predispose American pitchers to greater risk of elbow injury. Japanese pitchers may have increased risk of shoulder injury due to greater normalized horizontal adduction torque and greater abduction angle. Japanese pitchers may be able to reduce their shoulder torque and risk of injury by shortening their stride, reducing their lead knee flexion, and decreasing their throwing arm abduction.Clinical Relevance:Understanding anthropometric, kinetic, and kinematic differences between pitchers from the 2 countries may be of value to clinicians and coaches working to maximize performance of the pitchers while minimizing the risk of injury.

Issei Baseball: The Story of the First Japanese American Baseball Players by Robert K. Fitts

Reviewed by: Issei Baseball: The Story of the First Japanese American Baseball Players by Robert K. Fitts R. Zachary Sanzone Robert K. Fitts. Issei Baseball: The Story of the First Japanese American Baseball Players. Lincoln: University of Nebraska Press, 2020. 344 pp. $29.95. Not everyone knows that the Japanese love baseball. Next to the United States and Latin America, Japan’s love for baseball knows no bounds. While this tidbit wouldn’t surprise most avid baseball fans, few of them actually know the extent of Japanese baseball history. As a baseball writer and historian, I didn’t know nearly as much as I thought I did. I knew about Japanese pitcher Eiji Sawamura, who in 1934 at the age of seventeen struck out Babe Ruth, Jimmie Foxx, Charlie Gehringer, and Lou Gehrig. I also knew that General Douglas MacArthur wanted the Japanese to start playing baseball as soon as possible after their surrender in September of 1945 to create some semblance of normalcy again. But between those two facts, I knew nothing at all about Japanese baseball, which is why I was excited to read and review Issei Baseball: The Story of the First Japanese American Baseball Players. Written by Robert K. Fitts, who also authored Banzai Babe Ruth: Baseball, Espionage, and Assassination during the 1934 Tour of Japan, Issei Baseball is the story about Japanese immigrants who came to America at the turn of the twentieth century. They formed the first Japanese professional baseball club, playing teams throughout the American Midwest between 1906 and 1911. Before I picked up this book, I didn’t even know that there was a Japanese baseball team in America in the early twentieth century. But through Fitts’s engaging and well-researched book, readers not only learn about the young Issei (Japanese immigrants), and the bigotry they faced throughout their playing days but also learn about how these players helped create a positive outlook on the Japanese for Americans. Fitts’s introduction provides a brief but engaging overview of baseball and the Japanese, effectively setting up a strong context that readers will be able to understand and appreciate. We initially learn that baseball came to Japan along with Commodore Matthew Perry in 1853. His arrival led to the breakdown of Japan’s efforts to remain isolated, which led to a modern Japan. Wanting their children to be able to adapt more easily to Western culture as the twentieth century approached, Japanese families sent their kids to private schools where they learned to play the game of baseball. Nisei—Japanese people born outside Japan—used baseball as a way to bring people in their neighborhood together to discuss business and local issues. During World War II they played in the internment camps as a way to maintain morale in the face of oppression. While the book itself focuses on the pioneers of Japanese American base-ball, [End Page 212] all this knowledge about baseball’s role in Japanese history strongly compliments the narrative. I was particularly interested to learn more about the Japanese players’ American barnstorming tour in 1906. The tour, which lasted over half a year, saw American entrepreneur Guy Green’s Japanese Base Ball Club cover 2,500 miles and play around 170 games. What makes this chapter, and the book itself, so engaging is the brief historical references that Fitts makes throughout the book that give more meaning to the places where the team played. For example, the team played in Irving, Kansas where an 1879 tornado killed a girl named Dorothy Gale, which allegedly inspired L. Frank Baum to write The Wizard of Oz. Something else I found particularly interesting was how people in Topeka, Kansas were obsessed with Japanese culture. Ads for Japanese goods ran in local newspapers while local women dressed in traditional Japanese clothing for tea parties. Fitts’s ability to briefly but clearly reference these pieces of information breathes life into the book that many authors cannot effectively do. He’s able to balance the details of his narrative without going off on tangents or giving additional unnecessary information. Fitts’s use of quotes lifted from newspapers that covered the game is also very effective...

Out-of-Hospital Cardiac Arrests During the Japanese Professional Baseball Championship Series

Because the Japan Professional Baseball Championship Series (Japan Series) is a stressful sports event, it is possible that watching Japan Series matches may increase the risk of cardiovascular events. Therefore, we investigated the potential association between the Japan Series and the incidence of out-of-hospital cardiac arrest (OHCA) events. National registry data for all cases of OHCA between 2005 and 2014 from 47 prefectures of Japan were obtained. We used a time-stratified case-crossover design with a conditional Poisson regression model to compare OHCA events during the Japan Series with those events that occurred during the periods except for dates of the Japan Series. The estimated associations for each prefecture were pooled at the nationwide level using a random-effects meta-analysis. In total, 666,020 OHCAs of presumed cardiac origin were reported during the study period. On days of Japan Series matches, the pooled relative risk of OHCA was 1.033 (95% confidence interval 1.012 to 1.055; p = 0.002; I2 = 3.5%, P for heterogeneity = 0.405). Stratified analyses by gender revealed that the substantial increase in OHCA during the events was observed for men, whereas we found no significant increase for women. We also found a considerable rise in OHCA among patients aged ≥65 years; however, there was no significant evidence of increased risk in those aged 18 to 64 years. In conclusion, stressful baseball match is associated with an increased risk of OHCA. Prevention measures for severe emotional stress-related OHCA should be implemented, particularly for elderly men.

The analysis based on principal matrix decomposition for 3-mode binary data

Recently, principal points for a multivariate binary distribution (Yamashita and Suzuki, 2014, 2015) have been proposed as the binary vectors that optimally represent a distribution, in terms of the average Euclidian squared distance between a multivariate binary distribution and the vectors. In this paper, we proposes a new analysis procedure for 3-mode binary data, based on principal points for a multivariate binary distribution (Yamashita and Suzuki, 2014, 2015). Moreover, we propose a method that decomposes principal matrixes for 3-mode binary data into a small number of vectors based on vector products. In order to investigate our method's applicability to real-world data, we use the method to analyse 3-mode structured data from annual all-star games for Japanese professional baseball.

The analysis based on principal matrix decomposition for 3-mode binary data

Recently, principal points for a multivariate binary distribution (Yamashita and Suzuki, 2014, 2015) have been proposed as the binary vectors that optimally represent a distribution, in terms of the average Euclidian squared distance between a multivariate binary distribution and the vectors. In this paper, we proposes a new analysis procedure for 3-mode binary data, based on principal points for a multivariate binary distribution (Yamashita and Suzuki, 2014, 2015). Moreover, we propose a method that decomposes principal matrixes for 3-mode binary data into a small number of vectors based on vector products. In order to investigate our method's applicability to real-world data, we use the method to analyse 3-mode structured data from annual all-star games for Japanese professional baseball.