The purpose of this study was to ascertain the process by which the physical education profession was established during the period of the American Association for the Advancement of Physical Education (AAAPE, 1885-1903).
At first, the large majority of physical educators who joined the AAAPE were intended to rise to the social position of gymnastic teachers. They recommended their physical training system, which had been proved through the scientific method of anthropometry. They considered that school physical education should be a compulsory subject. In their discussion of the profession, it was confirmed that a medical degree should not be considered a sufficient qualification for a position as a physical training director and/or gymnastic teacher. It was concluded that a proper educational course was necessary to qualify a person as a director of physical training.
Professional views of gymnastic teachers toward sport were characterized by disgust or prejudice against violent competition and excessive exercise. Sport was considered incompatible with the normal practice of gymnastics education. However, physical educators who were typically able to take positions in the YMCA were already enthusiastic about games and sports. Therefore they had to modify games and sports according to educational needs, and apply these activities to build well-balanced all-round individuals. It is evident that this well-disposed action toward sport led to gradual progress in this direction.

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This article expands some historical perspectives on “popular sport” based on the following three case studies: (1) Interactions between foreign sport and rural sumo wrestling in the village of Shiojiri, Nagano prefecture, during the Taisho Democracy Period. (2) The historical development of traditional Japanese boat racing in the area known as Tamaeura in Hagi, Yamaguchi prefecture. (3) Modern reconstruction of folklore and physical competition following the agrarian revolt known as the “Chichibu Jiken” in Saitama prefecture in 1884.
Having to compete with festive folklore, the main emphasis of physical education and sport in modern Japan was placed on civilization and enlightenment. Thus, the establishment aimed to develop thrifty and hard-working citizens who served the state and capital. However, there were moments when opposition, deviation and autonomy occurred in the daily lives of the masses, and it was clear that they could not be controlled unitarily. For the masses, traditional physical competition and sport were not only hobbies, forms of entertainment or means of improving self-discipline or physique, but also provided a medium for expressing their desire for solidarity and social growth.
What is “popular sport”? It is not a solid cultural entity but a complete panorama of physical competition and sport from the viewpoint of the masses. The “history of popular sport” aims to analyze and represent this phenomenon historically in relation to the total sphere of daily life. In such research, the concept of the masses has significance in terms of “method”, “standpoint” and “strategy”.

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Joint mobility i.e. flexibility, is generally considered a physical ability by which to coordinate movements. It is also known that keeping an adequate range of motion (ROM) of the spine is very important for executing smooth and safe exercises with aging. In previous studies, flexibility was evaluated on the basis of ROM of the trunk or lumbar spine during trunk flexion and extension, and changes in ROM with age have been widely reported. Although it has been pointed out that the thoracic and lumbar spine move in a different manner during flexion and extension, there has been no systematic study focusing particularly on ROM of the thoracic spine with age.
The objective of the present study was to examine the effects of aging on ROM of both the thoracic and lumbar spine during trunk flexion and extension by evaluating kyphosis and lordosis while standing at rest. The subjects were 165 (male 81, female 84) healthy volunteers ranging in age from 11 to 92 yr, with no orthopedic problems and who did not perform regular intensive exercise. The subjects were asked to stand still to allow measurement of kyphosis and lordosis angles, and then to perform intentional thoracic spine flexion, maximal trunk flexion and maximal trunk extension. The movements were videotaped and analyzed by using a 2-dimensional analysis program (Frame-DIAS-2 V3, D.K.H., Tokyo.) ROM of the thoracic and lumbar spine during trunk flexion and extension was evaluated from the coordinates of three sets of newly designed markers.
The present results showed that thoracic ROM during trunk extension decreased significantly with age for males. For females, a significant increase of kyphosis and a significant decrease of thoracic ROM during trunk extension with age was apparent. On the other hand, no significant effects of aging were observed in kyphosis for males and in thoracic ROM during trunk extension for females. In addition, a significant decrease of lumbar lordosis and ROM were confirmed for both males and females.
From the results of this study, it is suggested that the effects of aging differ in the thoracic and lumbar spine, and it is considered that joint mobility of the thoracic spine and lumbar spine should be evaluated independently.

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The purposes of this study were to elicit experiential knowledge from expert baseball pitchers and baseball coaches, to elucidate key coaching points related to movement in baseball pitching, to classify them into categories, and to investigate any commonality among them. Semi-structured interviews were conducted with four former Japanese professional baseball pitchers and seven expert high-performance (national level) Japanese baseball coaches. Each interviewee was requested to comment on the pitching of 25 amateur baseball pitchers (11 junior high school, 8 high school, and 6 collegiate baseball pitchers), which had been videotaped beforehand. The comments were recorded, dictated literally, and divided into segments on the basis of meaning unit. Based on the properties of the various meaning units, some were gathered and classified into categories. For this process, we conducted a member check and triangulation to improve reliability and validity. We extracted 3283 units and classified them into 14 general categories and 71 specific categories. The most frequent category was “trunk open and quick turn during the stride and arm cocking phases”. However, this accounted for only 5.5% of the total meaning units. The next most frequent categories were “weighting on the pivot foot in the balanced position and during the stride phase” (4.7%) and “the throwing arm movement during the stride phase” (4.6%). The contents of all categories covered various aspects of movement. Among the relatively frequent categories, a few elicited the same opinion among the interviewees, but some had different opinions even about the same pitcher. These results suggest that there is a diversity of coaching points among coaches, and that it is important to know the categories that are determinative and those that should be chosen selectively.

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The present study investigated factors affecting the evaluations of Judo referees and judges accredited with A, B and C licenses (n=100 each) after observing four different throwing techniques from four directions. Referees and judges were asked to evaluate the throwing techniques without being allowed to freely select their field of view or hear the sound of impact between the thrown competitor and the mat. In addition, we investigated the reasons for differences in evaluations according to the direction of view by focusing on contact between the thrown competitor and the mat.
1. Significant interactions were observed for only one of the four throwing techniques. In addition, a significant main effect was observed for all four throwing techniques. Based on these findings, the following factors appeared to influence the evaluations made by the referees and judges with regard to throwing techniques: 1) direction of view, 2) refereeing level, and 3) a combination of both the direction of view and refereeing level. In addition, differences in evaluations were considered highly likely to have been caused by individual effects related to the direction of view and the level of refereeing.
2. When the execution of a throwing technique prevents referees and judges from clearly observing body contact with the mat, the technique is evaluated by considering the series of body movements and estimating contact between the body and the mat based on available visual data. This may also result in differences of evaluation.
3. The average scores awarded for throwing techniques by A- and B-licensed referees and judges were significantly higher than those awarded by C-licensed referees and judges. Although the difference between A- and B-licensed referees and judges did not reach significance, A-licensed referees and judges tended to award higher average scores than B-licensed referees and judges. This suggests that more qualified referees and judges evaluate throwing techniques more accurately. The reason for this is that less qualified referees and judges tend to undervalue throwing techniques.

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The purpose of this study was to identify students' expectation of teachers' behavior in physical education classes, and to examine the relationship between this expectation and students' self-perceived competence. The total of 1192 junior high school students (613 boys and 579 girls) completed two kinds of questionnaire. One of them was used to detect types of behavior students expect from their teachers, and the other to evaluate students' level of physical competence and perceived control. Exploratory and confirmatory factor analysis revealed four expectation factors for teacher behavior (enriched learning environment, equal relationship between teacher and student, criticism, encouragement). The results showed that girls had higher expectations than boys for all teacher behavior factors, except for criticism. In fact boys expected more criticism than did girls. Furthermore, there was a moderate positive correlation between perceived control and three expectation factors of teacher behavior (enriched learning environment, equal relationship between teacher and student, encouragement), despite a weak correlation between physical competence and all students' expectation factors. These results indicate that girls expect closer and more positive interaction with their teachers than do boys. In addition, it was also revealed that perceived control had stronger effects on students' expectations of teacher behavior during physical education classes in comparison to physical competence.

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This study investigated the applicability of item response theory to a questionnaire survey. Parents of 288 kindergarten students were asked about their children's food tastes and eating habits. The Squared Simple Logistic Model, which is an unfolding model of the item response theory, was applied to the food survey data. Food taste parameters and individual taste parameters for food were computed using the maximum likelihood method and Newton-Raphson method. The applicability of item response theory to the questionnaire survey was examined by considering the correlations of food taste parameters and eating habits, the fitness of the model to the data, and comparison of the results with Quantification Theory Type Three. The following results were obtained:
1) Food taste parameters corresponded to the degree to which a child likes the taste of healthy/unhealthy food. Food taste parameters were significantly correlated with bad eating habits, and fitted the model sufficiently.
2) Considering the information function of the scale comprising food taste parameters, this scale was not a screening test type but rather a selective test type or a discriminating test type, and successfully discriminated among three types of eaters: “problematic,” “intermediate,” and “good.”
3) Using Quantification Theory Type Three, which, unlike item response theory, does not assume any latent traits, two sets of food taste category weights for individual data, divided randomly, were computed. The correlation between the two sets of category weights was lower than that of food taste parameters selected using item response theory. This finding indicated the advantage of item response theory over Quantification Theory Type Three from the standpoint of parameter stability.
4) Finally, to enhance the practicability of this scale, a conversion table for typical data with a high likelihood of fitting into a parameter we had already obtained, as well as showing a good fit to individual taste parameters, was devised.

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In 1903, the Japanese Ministry of Military Affairs revised the manual of military gymnastics, the so-called taiso kyohan. In 1913, the Ministry of Education formulated the syllabus of gymnastics to be taught in schools, gakko taiso kyojyu yomoku. It has generally been considered that this syllabus was based mainly on the Swedish system of gymnastics. In the present study, I set out to clarify whether many of the gymnastic exercises performed on apparatus (except for hand-tools) as specified in the manual were designed for secondary school boys in the syllabus. The period studied was that from the time when the report taiso yugi torishirabe hokoku, meaning “an investigation of gymnastics, play and games in schools” was published in 1905 by the research committee authorized by the Ministry of Education, until the publication of the 1913 syllabus. The Ministry of Education had planned the syllabus in response to a demand from the Ministry of Military Affairs to formulate a school gymnastics program based on military lines, because the report had proposed the abolition of military gymnastics in schools. My research involved not only the use of general documents but also analysis and comparison of tables describing each phase of the exercises published in the manual, the report itself, and the syllabus, in order to verify relationships among them.
Based on the available materials, I concluded it was far from certain that there had been an insistence to include military gymnastics in school gymnastics, in spite of the fact that some military gymnastic exercises were listed in the report. Accordingly, the Ministry of Military Affairs had requested the Ministry of Education to devise a school gymnastics program based on military lines. “Heaving movements”, a component of the original Swedish gymnastics, which had been translated as jyoshi no undo, meaning “arm-movements”, was divided into two parts in the syllabus. One was jyoshi no undo, meaning “arm-movements”, except for exercises performed on apparatus, and the other was the new term, kensui undo, meaning “chin-up movements”, which literally covered a broad range of exercises including chin-ups and pull-ups on gym apparatus, because the two terms kensui undo and cyoyaku undo, meaning “jumping and vaulting movements”, were necessary in order for the syllabus to comply with the demand for military gymnastics. Military gymnastics was one of two main gymnastic systems in the syllabus, because the two partitions were composed of military gymnastics, as was the case for Swedish gymnastics.

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Background: Developmental and gender difference in motor ability among preschool-aged children were investigated by reference to performance of test items, based on measurement score.
Purpose: The primary aim of this study was to verify development and gender difference in Innate Potential Motor Ability (IPMA), which is defined as non-differentiable ability, and the secondary aim was to explore the relationship between motor performance score and test item characteristics.
Method: We tested 209 preschool children using 20 test items twice a year for two years, and derived mixed longitudinal data covering six periods during three years. Average standard scores were calculated for every term in order to derive estimates for the 20 items overall. The test items were assessed from the viewpoints of main functional organ, promptness of performance, formation of movement, physical fitness, and movement skills, and the relationships between these items and the average standard scores of motor performance were studied by multiple regression analysis using accumulated data representing dummy variables. In order to solve problems related to multicollinearity, principal components regression analysis was employed.
Results and Discussion: The regression formula was shown to be predictive. IPMA for boys and girls, as represented by a partial correlation coefficient for every measurement item, was shown to develop with aging. There was no gender difference of IPMA among this cohort of preschool-aged children. The strongest relationship was evident between IPMA and motor performance score. Without IPMA, promptness of performance showed a relatively stronger relationship with motor performance score than the other characteristics of the test items. Internal promptness of performance, which demonstrates an individual's pace, was related to performance development. There was a weak relationship between elements of physical fitness and motor performance score.

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The main purpose of this study was to verify the process of formation and development of the concept of aiki used by Morihei Ueshiba, the founder of Aikido, and his disciples. The main points can be summarized as follows:
1. The term aiki has been used to refer to particular martial arts techniques and to a spiritual state that can be experienced by practicing Aikido. Morihei taught aiki as a technique, as shown in the memorandum of the Japanese Imperial Navy Admiral Isamu Takeshita around 1930. Kisshomaru Ueshiba, Morihei Ueshiba's son, also introduced these techniques in his book, “Techniques of Aikido” (1962), etc. However, neither Morehei Ueshiba nor his son explained about aiki in detail. Kenji Tomiki and Gozo Shioda used aiki as a term of technique, but they do not seem to have taught techniques under the name of aiki.
2. Onisaburo Deguchi, the head of Omoto-kyo, used the expressions “the union between a kami and a mortal” in 1921 and “the great love of the kami” in 1935, which Morihei later emphasized in relation to aiki. Omoto-kyo heavily influenced the building of Morihei's thoughts on aiki and Aikido. Aiki was likened to the great love of the Universe, Heaven and Earth, or the kami who nurtures all nature and mortals. In short, a) aiki is the union between the kami as love, and mortals, hence the practice of aiki is the purification of mind and body; b) the practice of Aikido creates a paradise for mortals on earth; c) because the kami does not oppose anyone, a practitioner does not oppose in Aikido. Morihei's thought influenced the policy of the succeeding organization of Aikido through Kisshomaru.
3. Morihei's four main pupils inherited his thoughts through several arrangements. Shioda explained aiki as “a technique for following the laws of nature”. Tohei insisted that aiki is “the union between the ki in heaven and earth and a mortal”. Sunadomari interpreted aiki as a combative technique and a divine work. Tomiki understood the term in two ways: one is a technique that falls into the category of kuzushi (balance-breaking), and the other is the unity of ki (energy) between nature and man. As to the way that Aikido should develop in the future, we need to study further Morihei's thoughts and their development under his pupils.

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The present study was performed to investigate the energetics of surface events (SE) in finswimming by analyzing the concepts of critical velocity (Vcri) and anaerobic swimming capacity (ASC). Ten finswimmers (five males and five females, aged 24±6 years), who were members of the Japanese national team, performed maximal effort swimming over five test distances (100 m, 200 m, 400 m, 800 m, and 1500 m). The distance-time relationship for the 200-m, 400-m, and 800-m distances showed a linear relationship (r²>0.99) in all subjects. Therefore, Vcri was calculated for these three distances, and ASC was defined as the y-intercept of the regression line between distance and time. A significant correlation was found between the mean velocity (V-) over each distance and Vcri (r=0.76-99). ASC was significantly correlated with V-100 m, V-200 m, and V-400 m (r=0.69-81). Furthermore, ASC was significantly correlated with the residual error of V-800 m (r=0.90) or V-1500 m (r=0.71) calculated by regression analysis of the relationship between Vcri and V-800 m or V-1500 m. The results of this study suggest that aerobic performance contributes to finswimming performance over distances ranging from 100 m to 1500 m. Although anaerobic performance also contributes to performance over distances of less than 400 m, it makes very little contribution over distances of 800 m and 1500 m.

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This study focuses on the early theory of play in the school (“Schulspiele”-Theorie) of Konrad Koch, who advocated his “play movement” (Spielbewegung) at the Martino-Katharineum gymnasium in Braunschweig at the end of the 19^th century.
According to Koch's “Schulspiele”-Theorie, sports education shows isolated pupils how to conform to norms on their own initiative, i.e. following rules and norms as a requirement in sports, and also improves self-discipline. However, at least at the inception of the thesis of play in the school (“Schulspiele”-Thesis) written in 1878, the school was placed as an associate between “home and family” and “nation”, where not only “lessons” were required, but inside the free gymnastic group (freie Turnerschaft) a community was to be built on the basis of an independent connection between teachers and students, as well as amongst the students themselves. The ideal form for this formatted collective was not further defined by Koch, who did not intend to have this collective focusing on “nation”, but rather aimed to build this on the basis of a civil collective. Although at this time Turnern idolized anti-foreign nationalism, Koch admired the significance of the English style of sports education. One can say that the “Schulspiele”-Theorie based on a civil collective had aims that were quite different from gymnastics in school (Schulturnen) that valued nationalism.
Nevertheless, by the turn of the century, Koch had also published an extremely militaristic thesis. At this time, the collective building based on play in the school (Schulspiele) was to be described as something that was clearly dependent on the “nation”. Future issues will focus on how and in which way Koch's “Schulspiele”-Theorie subsequently found its way into forms of authority in modern nations.

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The first purpose of this study was to examine the influences of explicit and implicit perceptual training on the reaction-time and accuracy of pitched ball anticipation. The second purpose was to examine transfer effects to a new pitcher. Twenty-eight varsity baseball players participated in this study. They were randomly assigned to an explicit instruction group, an implicit instruction group, or a control group. Forty-eight test trials and 72 perceptual training trials were administered on the first day of the experiment. On the second day, 48 test trials followed by 144 perceptual training trials were administered. The third day consisted of 48 test trials. The test consisted of evaluation of the pitch location, pitch type, and both pitch location and type. Anticipatory cues were introduced to the explicit instruction group only. Participants in the implicit instruction group were instructed to react intuitively. Participants in the control group performed only test trials. The results indicated that the level of awareness of anticipatory cues was significantly lower in the implicit instruction group than in the explicit instruction and control groups, whereas that in the explicit instruction group was significantly higher than in the control group. These findings suggest that instructions demanding an intuitive reaction inhibited awareness of anticipatory cues. Moreover, in both the explicit and implicit instruction groups, the speed of anticipation for pitch location and for both pitch location and pitch type were improved significantly by the 72 perceptual training trials, whereas no such change was observed in the accuracy of anticipation. No improvement in speed or accuracy was observed in the control group. These results indicate that explicit and implicit perceptual training yields similar improvements of anticipatory skills and different levels of awareness about anticipatory cues. No transfer effects were observed in this study.

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PURPOSE: The aim of this study was to examine the differences in physical fitness level between those who continued to participate and those who dropped out during a 5-year longitudinal study.
METHODS: The subjects were 254 older Japanese men and women, aged 60 y and over (69.6±5.6 y), who lived independently and were able to participate in physical fitness testing only at the baseline (drop-out group: n=163, 70.1±5.5 y) or every year from 2000 to 2005 (follow-up group: n=91, 68.7±4.5 y). Seven physical-performance test items related to activities of daily living were measured. In addition, a questionnaire was used to collect information regarding self-reported exercise habituation, joint pain, health-related quality of life and health condition. Significance of differences between the drop-out group and follow-up group were tested using Student's t test and analysis of covariance (ANCOVA). Logistic regression analysis was performed to explain characteristics of physical fitness status in the two groups. The level of statistical significance was set at P<0.05 for all analyses.
RESULTS: At the baseline, those in the drop-out group were older, had lower levels of physical fitness and more joint pains, and were physically less active than the follow-up subjects. However, health-related quality of life and health condition did not differ significantly between the two groups. In a multivariate logistic regression analysis adjusted for age and sex, those in the drop-out group had a slower walking speed around the two cones in a figure 8 (odds ratio 1.23, 95% confidence interval 1.12 to 1.35), and were non-habituated to exercise (odds ratio 1.72, 95% confidence interval 0.97 to 3.06).
CONCLUSION: These results suggest that older adults who drop out after the baseline in physical fitness tests are older, have lower physical fitness, and are physically sedentary.

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Japanese married women only began participating widely in sports after the Tokyo Olympic Games in 1964. It is often said that sports activities by housewives indicated their liberation from isolated domestic life, thereby promoting gender equality. However, close examination of the systemic characteristics of the ‘Mothers’ Volleyball’ movement (based on its ideology, competition rules and the nature of its routine activities) has shown that these activities possess both a recycling structure that releases housewives from their homes temporarily and reflects the participants’ ‘housewifeliness’, thereby reinforcing the separation of roles between the sexes.
In order to clarify by whom and for what purpose this recycling structure was created, this paper focuses on the organizing bodies (sponsor organizations, supporting companies and other bodies that organized and ran the national championships, incorporating the systemic characteristics of Mothers’ Volleyball), analyzing the reasons for their involvement with the movement and the benefits they derived from it. The results show that the periodic reflection of housewifeliness, which housewives needed in order to continue in their role as housewives, was necessary for the economic and social benefit of all the organizations involved, and that this is why these organizations committed themselves to the movement.
Participating in sports freed housewives from the routine of daily home life, and activities such as helping to organize competitions promoted their socialization and changed their image from that of ‘isolated housewife’ to ‘sporting housewife’ and further to ‘independent housewife’. The recycling structure mentioned earlier can therefore be thought of as being a directional spiral, and the organizing bodies that ran the national championships can be said to be its drivers.
This spiral, which helped to reproduce ‘housewifeliness’, supplied society with good-quality labour for sustaining Japan's rapid economic growth, which was a political issue in the 1970s. The participation of housewives in sports as one of the activities of parent-teacher associations and women's associations can also be said to have contributed to local revitalization, another political topic at that time. Meanwhile, making sports one of their routine, repeated activities made housewives’ lives more satisfying, so that Mothers’ Volleyball acted as a medium for the formation of a conjugate relationship between housewives and society.

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The purpose of this study was to derive criteria for observational evaluation of the high jump (scissors jump) to allow examination of the essential elements of high jump performance by upper-grade elementary school children that contributed to achievement of the target record.
The subjects of this study were 46 children (26 boys and 20 girls) who attended instruction classes in high jump in both the 5th and 6th grades. In the class who practiced high jump continuously for 2 years, motion during the scissors jump was analyzed and evaluated longitudinally according to the observational criteria we had derived, and technical elements that contributed to achieving the high jump target record were extracted.
The main results were as follows.
1. The criteria derived for observational evaluation comprised 6 items and 5 stages, which were shown to have constant validity, objectivity and reliability for evaluating the series of motions during the scissors jump.
2. In the 5th grade, it was preferable to learn the technique of take-off with the whole body extended, raising the lead leg highly with the knee extended, and raising the take-off leg highly with the hip joint widened.
3. In the 6th grade, it was preferable to learn the technique of run-up in which speed was maintained and rhythm was improved in the last 2 or 3 steps, and take-off with the upper body raised from a backward posture. The technique for take-off made the best use of rhythm and speed in the run-up, derived progressively from the content acquired in 5th grade.
4. Though the content of study should be appropriate for the developmental stage, it is preferable to place more emphasis on techniques related to run-up and take-off for upper-grade elementary school children.

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In this study, the unsteady aerodynamics of a knuckle ball in soccer were investigated. The characteristics of the fluid force, i.e. the magnitude and frequency acting on the knuckle ball, were analyzed through comparison with those of the straight ball using high-speed video cameras. Furthermore, the fluid flow around the knuckleball in flight was visualized using a smoke agent (titanium tetrachloride), and an attempt was made to clarify the fundamental fluid mechanics expressed by the knuckle ball as well as to analyze the vortex dynamics. It was found that the vertical acceleration of the knuckle ball tended to vary greatly (oscillate) in comparison with the acceleration of a straight ball, despite the fact that both are influenced by gravity. Moreover, in the case of the knuckle ball, the peak value of the vortex lift reached approximately 2.0 N, which was larger than the value of approximately 0.5 N for an instep kick. This vortex lift fluctuated greatly with time and was thought to be a highly unstable phenomenon. When the large-scale vortex structure of the knuckle ball was studied, successively shed vortex loops transformed and merged, and a few massive vortices formed an extended vortex street structure. Moreover, when the vertical fluctuation along the wake axis of the large-scale vortex structure was studied, evidence of unsteady wave oscillation (undulation) was observed. This large-scale structure of the far wake was conjectured to indicate traces of vortex motion at the time of vortex shedding, and the effect of this motion was thought to have a direct influence on the motion of the ball. Furthermore, the knuckle ball was observed to have an average vortex lift force frequency of approximately 3.5 Hz. A comparison of this vortex lift frequency and a vortex oscillation frequency indicated that these frequencies tended to act in unison with a high statistical correlation (r=0.83, p<0.01). Thus, it is considered that the oscillation of the large-scale vortex structures of the knuckle ball was the fundamental mechanism responsible for creating the fluctuating forces acting on the knuckle ball.

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This study examined the physique, physical fitness and motor ability of soccer players, especially junior youth and youth players of “J-League” clubs, using relatively common field test items in accordance with the Japan Football Association (JFA) Physical Measurement Guidelines (2006). We also compared the physique, physical fitness and motor ability between those who were promoted and those who retired from clubs for each generational category (top team group and second team group for the professional category) in an attempt to identify factors that significantly influence selection to higher categories.
The study subjects were 213 male soccer players who were affiliated to a team (aged 19 years or older) in the Japan Professional Soccer League (J-League) or its subsidiary clubs, including the youth team (16-18 years) and the junior youth team (13-15 years), between 2006 and 2008.
All subjects were compared for the following items: body height, body weight, percentage body fat, 10-m run, 30-m run, 50-m run, shuttle run (10 m×5), STEP 50, vertical jump, standing five-step jump, and multi-stage shuttle run. The measurements were also compared between those who were promoted and those who retired from the club for each category using the t-test and discrimination analysis. The results revealed that the factors of physique, physical fitness and motor ability that significantly influenced the promotion or retirement of junior youth and youth players were those related to physique (especially body weight), speed and agility. Power-related factors were more important in youth players, but were less influential than the above-mentioned factors. The influence of endurance-related factors appeared to be even smaller. The field test items used in the present study are considered valuable for use in training practice in that they can be performed relatively easily and allow selective factors for each category to be determined to some extent.

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The purpose of this study was to investigate gender- and event-related differences in trunk muscle size in high school athletes. Magnetic resonance images of the trunk region were obtained for a total of 204 female and male athletes majoring in sprinting, long-distance running, throwing events, volleyball, badminton, boat events, canoeing and judo. Thirty-six untrained high school students (Control) also participated. From the images, muscle volumes of the rectus abdominis (RAV), internal and external oblique muscles (OBV), psoas major, quadratus lumborum, erector spine muscles, and the total muscle compartment (TotalV) were estimated. Fat-free mass (FFM) was also measured by air-plethysmography, and the estimated muscle volumes per FFM were compared to assess gender- and event-related differences in trunk muscularity. Predominant development of trunk muscles on the non-dominant side was observed in athletes involved in throwing events, badminton and volleyball, regardless of gender. While males showed significantly larger values than the females for all of the estimated muscle volumes in terms of absolute values, there was no gender difference in RAV/FFM, although males still showed significantly larger values in the other muscles after taking difference of body size into account. Judo and throwing-event athletes showed the largest TotalV in terms of absolute value; however, sprinters and badminton players showed the largest values of TotalV/FFM, suggesting predominant development of trunk muscles in these sports events. Judo athletes showed predominant development of only OBV, and no difference in trunk muscularity was found among volleyball athletes, long-distance runners and untrained control groups. These results demonstrate that trunk muscle size in high school athletes depends on the specialist sport event, and it is assumed that sport-specific motions/training could affect the development of trunk muscularity.

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