This study investigated the relationships between the kinetic factor of the swing leg and step frequency (SF) and step length (SL) during the top speed phase of a sprint. Sixteen male sprinters (age 19.3±0.6 years, height 1.74±0.06 m, weight 66.1±5.2 kg) performed maximum effort 60-m sprints. Video data from the 43.5- to 50-m section of the sprint were collected using a high-speed camera (300 Hz). SF index and SL index were calculated to exclude the influence of body height on the outcomes of interest. Torque and torque power of the hip and knee joints of the right leg were calculated during the swing phase of the right leg. The time of the swing phase of the right leg was normalized so that the take-off of the right foot, touchdown of the left foot, take-off of the left foot, and touchdown of the right foot were 0%, 100%, 200%, and 300%, respectively. For every 5% of normalized time, partial correlation analysis was conducted between the right leg kinetics and SF index (controlling SL index) and SL index (controlling SF index).
The SF index was associated with a large hip flexion torque and a large hip extension torque during 10–60% and 250–280% of the swing phase, respectively. Moreover, large peaks of the hip flexion torque and positive power were associated with a high SF index (r = -.718, p <0.01; r = .531, p <0.05, respectively).
The SL index was associated with a hip flexion torque during 20–30% of the swing phase, although there was no significant partial correlation between the SL index and peak hip flexion torque (r = -.381, p = .161). In addition, a high SL index was associated with early appearance of the peak hip flexion torque power (r = -.759, p <0.01). In conclusion, throughout the top speed phase of a sprint, a high SF index requires a large torque and hip joint power for the leg swing over a short duration, and a high SL index requires an early increase of hip flexion torque power.
Being overweight is a major risk factor for development of lifestyle-related diseases, and the sheer volume of current evidence that childhood obesity persists into adolescence and adulthood suggests the importance of rectifying obesity in childhood. The present study followed up children in the 1st to 6th grades of elementary school to examine whether being overweight was a continuous trend. In addition, increases and decreases in the adiposity of the students were examined in order to clarify fluctuations in their physical build. The subjects of the study were 3991 students (2046 boys and 1945 girls) attending all 68 schools in city U who were tracked for 6 years. The students were divided into 10th percentiles based on their degree of overweight. Using the median 45-55th percentile as a reference group, univariate logistic analysis was used to calculate the odds ratio of students who were overweight in the 1st grade remaining so in the 6th grade. It became clear that students in the 85th percentile or higher in first grade were 39.8 times more likely for boys and 21.9 times more likely for girls to be overweight in the 6th grade than 1st grade students in the reference group. Boys and girls who were markedly overweight in the 1st grade continued to demonstrate high degrees of obesity in the 6th grade. About 80% of both boys and girls who were overweight in the 1st grade of elementary school continued to be overweight in the 6th grade.
Based on the above findings, it is clear that the degree of overweight in the 1st grade of elementary school has a strong influence on the corresponding degree in the 2nd grade and thereafter, thus suggesting the importance of preventing overweight developing upon entry to elementary school.
The purpose of this study was to compare active drag during front-crawl swimming performed by competitive swimmers with passive drag acting on the same group of swimmers with a streamlined position at various velocities. Seven male competitive swimmers participated in this study, and the testing was conducted in a swimming flume. Active drag was evaluated for front-crawl swimming with upper and lower limb motion using a methodology that estimates the drag in swimming using measured residual thrust values (MRT method). Passive drag was measured by a load cell connected to the swimmers with a streamlined position using a stainless-steel wire. In each case, drag was estimated at six staged velocities ranging from 1.0 to 1.5 m/s. To compare the drags at various velocities, we calculated coefficients a and b by applying the measured force value at each velocity to the equation D = a vb (D: drag, v: velocity). The active drag estimated from the MRT method (a = 35.7 ± 5.3, b = 2.80 ± 0.22) was larger than passive drag (a = 23.6 ± 3.1, b = 2.08 ± 0.23). Furthermore, the difference between active and passive drag was large at high velocities. Therefore, it is possible that the effects of factors other than posture and/or body shape have a large influence on active drag, especially at high velocity.
To clarify the conceptual attitude of professional athletes, this paper presents 3 views on occupation using the main analytical framework proposed by Kunio Odaka. The first is the economic perspective. Referring to the content of the Japanese Standard Classification of Occupations, by clearly distinguishing this from other occupations in sports, professional athletes are defined as a profession “participating in competition or games and performing athletic competition.” From the viewpoint of income type and qualifications, we assume that numerous types of professional athletes exist. The second is the perspective of technical skill. Based on the discussions of Mitsuo Taketani and Tomihiko Sato, technical characteristics of athletes are defined as demonstration of their skills in accordance with sports structure as an objective law. Moreover, referring to the organization theory of Ikujiro Nonaka and Hirotaka Takeuchi, we point out that professional athletes are able to transform sports structure in terms of organizational creation. The third perspective of ethics considers the duties that are required of professional athletes. We conclude that their duties in relation to teammates are concerned with the “pursuit of victory through cooperative relationships.” In relation to opponents, such duties are “playing the game through a mutual relationship” and “pursuit of victory in an exclusive relationship.” With regard to spectators, such duties are concerned with “entertainment” and, in terms of the broad relationship to society, “the embodiment of social values”. These 3 aspects are diverse, and dependent on the extent of an athlete’s expertise.
The purpose of this study was to present a new perspective on the problem of attempting to lose a game on purpose through a consideration of whether doing so threatens the existence of sport. We began by hypothesizing the concept of “failed athletic contests”, which has been discussed in the field of sport philosophy, as jeopardizing the existence of this activity. We then examined the concept of “losing games on purpose” with reference to the “failed athletic contests” theory of Kawatani (2013). We examined 2 broad categories of “losing games on purpose”: one where defeat is clearly the goal, and the other where players deceive referees and spectators by behaving as though they want to win, while in fact actually trying to lose.
Kawatani claims that games where an ethos (internal purpose) is not achieved, even though the contest is based on athletes playing according to the rules, constitute “failed athletic contests”. He found that player commitment to winning is necessary as a condition in achieving the ethos of the game, suggesting that “losing games on purpose”in either category constitutes a “failed athletic contest” in that athletes are not committed to victory and the ethos is not established. On the other hand, it was also clarified that there is a dilemma for players in athletic meets when a commitment to winning is called for, but when this is occasionally in conflict with the ethos of individual games.
For the second category, it was also revealed that referees and spectators were not aware of the nature of such a defeat when it was concealed. This suggests that the second category of “losing games on purpose” is more problematic than the first.
The purpose of the present paper was to lay the groundwork for a “coaching philosophy.” In the first section, the article analyzes the term “coaching philosophy” from a linguistic perspective. The second section aims to clarify the definition by critical examination of the literature. The third section explores the reasons why coaches need a “coaching philosophy”. Through these processes, the proposed definition of “coaching philosophy”is presented as a “comprehensive statement of the ends aimed at as coaching principles, the basic guidelines that give coaches direction, and the values set by coaches in practice to develop, improve, and realize the excellence of athletes and teams”.
This study examined the psychosocial skills of high school extracurricular sports activities and their generalization to student daily life. In a preliminary study, we collected a wide range of psychosocial skills related to extracurricular sports activities experienced by members of high school sports clubs, and then selected questionnaire items that would be used in the present study. In Survey 1, a confirmatory factor analysis was conducted using data collected from 376 members of high school extracurricular sports clubs (265 males, 111 females) to develop two scales, one measuring psychosocial skills in extracurricular sports activities, and the other psychosocial skills in daily life. The validity and reliability of these two 9-subscale tools, both of which comprised the same items, were thus confirmed. In Survey 2, the two scales developed in Survey 1 were used to conduct three surveys of the same subjects over an interval of about 3 months, in order to determine the causal relationships between the psychosocial skills used in extracurricular activities and those used in daily life. A cross-lagged effect model was used. The study subjects were 137 high school students who were members of extracurricular sports clubs (73 males, 64 females). The results showed that the psychosocial skills needed for extracurricular sports activities could be generalized to student daily life. Generalization in the reverse direction, i.e. from skills used in everyday life to those used in extracurricular sports activities, was also evident. Furthermore, the results suggested that psychosocial skills used in extracurricular sports activities had a cyclical causal relationship with the skills used in everyday life. Finally, the significance of extracurricular sports activities and methods for actualizing this significance was discussed based on the study results.
Step parameters are associated with running economy (RE), but the relationship between these longitudinal changes remains unclear. In the present study, we aimed to clarify the relationship between changes in step parameters and RE at intensities below and above the lactate threshold (LT) in well-trained middle to long-distance runners and to acquire knowledge applicable to coaching. A total of 29 male university students training in distance running (age, 19.4 ± 1.0 yr; height, 171.3 ± 4.5 cm; body weight, 57.1 ± 3.6 kg) participated in the study. Participants performed multistage incremental treadmill tests to measure step parameters (ground contact time: CT; step length: SL; step frequency: SF; leg stiffness: kleg) and RE before and after 4 months of training. Since the LT speed of participants was 16.6 ± 1.1 km･h−1, intensities below, near, and above the LT were set at 13.8 and 15.0 km･h−1, 16.2 km･h−1, and 17.4 and 18.6 km･h−1, respectively. No significant relationships were observed between changes in RE and any of the step parameters at intensities below and near the LT. Moreover, although no significant relationship was noted between changes in RE and both SL and SF, there was a significant positive and negative relationship between changes in RE and CT and kleg, respectively, at intensities above the LT. Changes in kleg showed a strong negative correlation with CT changes at each intensity. It can be concluded from these findings that shortening the CT improves the RE for high-intensity running and that this variation is partly attributable to the improvement in kleg.
In high school baseball games, choosing when to bat influences the likelihood of winning, teams batting second having a significantly higher winning percentage. Three hypotheses can be considered for explaining this trend: the weaker school chooses to bat first (Hypothesis 1), an additional strategy change can favor the team that bats second (Hypothesis 2), and a tied score in a later innings favors the team that bats second (Hypothesis 3). However, to our knowledge, no study has directly tested these hypotheses. Therefore, we analyzed data for all 972 games of the Japan national high school baseball championship tournaments between 1996 and 2015, and the following 5 results were obtained. There was a trend in past Koshien tournaments for weaker schools to bat first when playing against stronger schools (52.8 percent, P = 0.091). The winning percentage for the former was 35.5%, which was significantly lower (P <0.001) than the chance level (50%). In addition, the winning percentage for batting first in games between schools with similar levels of past performance was 44.7%, which was significantly lower (P = 0.025) than the chance level (50%). In games between schools with similar levels of past performance, the winning percentage varied for teams batting first when the bottom half of each inning ended in a tie. In games in which teams were tied at the end of the 6th and 7th innings, the winning percentage of the team batting first was significantly lower (36.0%, P = 0.033; 34.0%, P = 0.016). In other words, Hypothesis 3 was supported, Hypothesis 1 was partially supported, but Hypothesis 2 was not supported. These findings indicate that the higher winning percentage for batting second is attributable to the fact that the weaker school regards itself as inferior to its opponent and therefore chooses to bat first (i.e., the weaker school chooses to bat first) and that the psychological pressure faced when batting first versus batting second differs when there is a tie in the later innings (i.e., a tied score in later innings favors the team that bats second).
The purpose of this study was to clarify the causal relationship between the “flow of a game” in basketball, defined as “the situation in which 4 periods, which consist of a division time of 10 minutes, advance gradually while having an influence on each other”, and its outcome, focusing on the interrelationships of the 4 periods. For this purpose, a hypothesis was established that the “flow of a game,” in which “factors causing changes in conditions” cannot be overlooked, consists of 4 periods, each creating opportunities that finally affect the outcome. In order to test this hypothesis, an analysis was performed of 1044 periods in 261 games in Japan’s strongest university league, the Kanto Men’s First Division League, based on the following 3 perspectives: (1) the importance of each period; (2) the mutual dependency among the periods; and (3) the relationship between the difference in cumulative scoring and outcome. The results were subjected to logistic regression analysis and covariance structure analysis, and the following 3 points were clarified: (1) Periods that influenced the outcome were the first, third and fourth, ranked in importance as third > first > fourth > second. (2) With regard to mutual dependency among the periods, the points difference in the preceding period in the sequence “first → second (cumulative),” “second (cumulative) → third (cumulative), “third (cumulative) →“fourth” created an opportunity in the following period. (3) A cumulative score difference of less than 8 points by the end of the third period was associated with a high potential for coming back to win. These findings should be applicable to coaching in various games under the official rules of the FIBA as new practical guidelines for closely analyzing the causal relationships between the unique “flow of a game” and outcomes in basketball that take place over 4 periods.
Causal relationships among perceived motivational climates in physical education classes, goal orientations, and “Zest for Living” were investigated reciprocally in junior high school students. This longitudinal study involved 1045 junior high school students (mean age = 13.9±0.8 years) who completed questionnaires on 5 occasions at 2-month intervals throughout the academic year. The measures used included a questionnaire on motivational climates in physical education (mastery climate, cooperative climate, and performance climate), a scale assessing goal orientations (student task orientation and student ego orientation), and a scale assessing Zest for Living. The validity of the 5-wave cross-lagged effect model was verified using structural equation modeling. The results of the study suggested the following processes: (1) The mastery climate and cooperative climate had positive causal effects on Zest for Living. (2) The mastery climate and cooperative climate had positive causal effects on Zest for Living through mediation of task orientation, and exhibited a positive cycle. (3) The performance climate had positive causal effects on ego orientation, but negative causal effects on task orientation. In conclusion, to enhance Zest for Living in junior high school students, it is important for teachers to cultivate a mastery climate and cooperation climate in physical education classes. In addition, the performance climate in physical education classes has an indirect negative impact on Zest for Living.
This study investigated the characteristics of force and power outputs during the trunk-twist exercise accompanying stretch-shortening cycle (SSC) movement focusing on the effect of SSC movement under different loads. Twenty healthy male college students who habitually exercised performed the bar twisting exercise. To investigate the effect of SSC on trunk-twist, participants performed the exercise using SSC (SSC condition) or without SSC (CON condition). For the SSC condition, participants rotated the bar clockwise; when the right side of the bar passed the mark (located at a bar angle of -75°), participants immediately rotated the bar counterclockwise. For the CON condition, the participants rotated the bar counterclockwise from the mark without using SSC movement. Three loads (0 kg, 10 kg, and 20 kg) were used under both conditions. Kinematic and kinetic data were calculated using data recorded with a motion capture system (250 Hz) and force platforms (1,000 Hz). The surface electromyograms (EMG) of 8 trunk muscles were recorded. The results of the analyses were as follows:
The trunk-twist torque and torque power under the SSC condition were significantly higher than those under the CON condition. Also, the SSC movement contributed to an increase in the peak angular velocity of the bar and trunk-twist, and shortened the time until the bar reached its peak angular velocity. The activity of the external oblique and latissimus dorsi, which are the agonist muscles used for the trunk-twist under the SSC condition, was significantly larger than under the CON condition. The activity of these muscles increased before the bar rotated counterclockwise, and contributed to an increase in the trunk-twist torque and torque power.
The angular velocity of the bar and trunk-twist decreased with increasing load. Meanwhile, the trunk-twist torque and torque power at 0 kg were highest. The EMG of the trunk-twist muscles showed no significant difference with increasing load.
These results suggest that using SSC movement during the trunk-twist exercise increases the force and power output of the trunk-twist, and that the latter decrease when the moment of inertia of the bar exceeds 10.36 kgm2.
The purpose of this study was to investigate the relationship between towing force during tethered swimming with different high-intensity interval training (HIIT) protocols using an elastic cord and front crawl swimming velocity, and to suggest the use of towing force parameters based on the results. Ten college male competitive swimmers participated in the experiments, which involved towing force measurements during front crawl swimming using 3 protocols of HIIT and time trials over 25m, 50m, 100m, and 200m. The 3 HIIT protocols were 8 sets of tethered 20s trials with 10s rest time intervals (“TABATA protocol”, 20―10s protocol), 8 sets of tethered 8s trials with 12s rest time intervals (8―12s protocol), and 2 sessions of 5 sets of tethered 5s trials with 10s rest time intervals (5―10s protocol). The swimmers were connected to a load cell using an elastic cord to measure the towing force during tethered swimming. The times taken for the 25m, 50m, 100m, and 200m distances were recorded by counting the number of frames in the video footages. The critical speed (CS) was calculated using a regression formula from the distances and the times required for the time trials. Simple linear regression analyses were performed to investigate the relationship between the towing force and mean velocity from the front crawl time-trials. The maximum towing force during all of the HIIT protocols was significantly correlated with the mean velocity for all distances and CS, and the regression formula was significant (p<0.05). Mean towing force during all of the HIIT protocols was significantly correlated with the mean velocity for 200m and CS, and the regression formula was significant (p<0.05). Logarithmic approximation of the time-force curves (peak and mean forces in each set) during HIIT was valid, and the y-intercept (towing force) of the approximation formula were significantly and negatively correlated with the mean velocity for all distances (25―200m and CS) and all HIIT protocols, the regression formula also being significant (p<0.05). From the viewpoint of feedback, the mean towing force during HIIT was useful for evaluating the workout effort during HIIT during tethered swimming using an elastic cord. The Y-intercept of the approximation formula from the maximal or mean forces during HIIT was best for evaluating the workout effort, although arithmetic processing of the logarithmic approximation will be required.
The purpose of this study was to evaluate the multistep drop jump (DJ) test in elite jumpers according to changes in test performance, ground reaction force, and lower limb joint kinetics with changes in drop height. Male jumpers (n=10) performed a DJ from 4 drop heights (0.3, 0.6, 0.9, and 1.2 m). The DJ-index was calculated by dividing the jump height by the contact time. The rate of change of the DJ-index (a/b) was the slope/intercept of the regression line (Y = aX+ b) derived from 4 values of the DJ-index for each subject. Jump motions in the sagittal plane and ground reaction force data were recorded using a high-speed camera and force platform, respectively. The DJ-index was lower at 1.2 m than at other drop heights. The contact time increased along with the drop height. There was no significant difference in jump height between the drop heights. The amount of negative work by 3 lower extremity joints increased with increasing drop height. The jump events performance (IAAF Score) and DJ-index at each drop height only showed a significant correlation at 1.2 m. The correlation between IAAF score and a/b was significant between these variables. According to individual characteristics, increased drop heights were associated with different patterns of change in the DJ index. Therefore, subjects were grouped according to characteristics using a/b as an index. Sub.A, who had the highest jump-event performance in the study, had participated in international meetings, and had won a medal at the World Junior Championships. The DJ-index for this subject at 0.3 m was close to the mean value, but at 1.2 m was highest among all the subjects. In contrast, the DJ-index for Sub.C at 0.3 m was highest among the subjects. However, the DJ-index decreased greatly with an increase from 0.3 m to 1.2 m. Therefore, to evaluate the performance of jumpers, it is important to use a varied range of heights, including a higher drop height (approximately 1.2 m), focusing on the rate of change with increasing drop height.
Using a temporal occlusion paradigm, the present study examined the anticipation of baseball catchers in a situation where they were required to give directions to teammates on play. Collegiate baseball catchers and fielders (n = 10 in each group) watched a series of video images, recorded from the catcher’s viewpoint, showing a simulated sacrifice bunt to the pitcher with no outs and a runner at first base. Each video image was occluded at 0 ms (T1), 370 ms (T2), 730 ms (T3), or 1100 ms (T4) after the moment of bat-ball impact. After viewing each occluded video image, the participants verbally answered whether the ball thrown by the pitcher would reach the second baseman before the runner touched second base (i.e., when the runner would be out), or whether the runner would touch second base before the ball thrown by the pitcher reached the second baseman (i.e., when the runner would be safe). The results indicated that the catchers showed higher anticipation accuracy and signal detection sensitivity than the fielders. Also, there was no difference in the effect of temporal occlusion between the catchers and the fielders. These results suggest that catchers have better anticipation ability resulting from higher signal detection sensitivity, compared with fielders from the early stage, by making use of the information available about the ball, the pitcher, and the runner. Furthermore, it was evident that anticipation accuracy was particularly increased for trials in which the runner would be considered out at second base, and that the judgment bias for selection of first base became smaller in the time period immediately after bat-ball impact (i.e., from T1 to T2). These findings suggest that the time period immediately after bat-ball impact includes information that can be used to reduce the tendency for avoiding the risk of a losing score resulting from erroneous judgment.
The purpose of this study was to clarify the exertion of torque and motion related to the generation of mechanical energy in both hip joints during baseball batting. The participants were 98 male amateur baseball players (body height: 172.6±5.6cm, body weight: 70.3±8.1kg, age: 19.0±1.9yr, career: 11.0±2.8yr). The batting motion was recorded using a motion capture system (10cameras, 250Hz), and the ground reaction forces acting on each foot were estimated using 2 force plates (1000Hz). Hip joint angles were expressed as Euler angle of the thigh relative to the lower torso. Hip joint torques were calculated using inverse dynamics. Other kinetic variables–e.g. hip joint torque power, mechanical work by hip joint torque–were also calculated. The main results were as follows:
1. Throughout the analysis phase, there was no significant correlation between the bat head speed at impact and the angles of both hip joints.
2. For the hip joint on the pitcher side, the generation of mechanical energy by flexion and adduction torque was large during the phase before maximum pelvis rotational velocity.
3. For the hip joint on the catcher side, the generation of mechanical energy by extension torque was large in the phase before maximum pelvis rotational velocity.
These results suggest that there are no differences in the kinematics of both hip joints depending on the bat head speed at impact. In addition, it is indicated that the ability to exert flexion and adduction torques for the hip joint on the pitcher side and the extension torque for the hip joint on the catcher side during baseball batting motion contribute to the generation of mechanical energy.
This study was performed to clarify the issue of Japan’s participation in the Games of the New Emerging Forces (GANEFO) held in Indonesia in 1963. Indonesia, which was officially banned by the International Olympic Committee from participating in the Olympic games due to its rejection of Taiwanese and Israeli participation in the 4th Asian Games in 1962, launched GANEFO as an alternative international sporting competition. Despite the fact that Indonesia invited Japan to GANEFO, the invitation was sent to neither the Japan Amateur Sports Association (JASA) nor the Japan Olympic Committee, but instead to the Ministry of Foreign Affairs (MFA). This was because GANEFO was, by nature, inseparable from Indonesian national policy, and Indonesia suggested that Japan participate in the newly launched competition as a political request. The MFA preferred to avoid political intervention in sport and left the decision to JASA. However, the cabinet of Prime Minister Hayato Ikeda tried to address GANEFO’s request in view of the relationship between Japan and Indonesia that existed in those days and the upcoming meeting between Prime Minister Ikeda and President Sukarno. In principle, Ikeda’s cabinet needed to refrain from intervening in GANEFO (as it was a matter of sport), but in practice it was unavoidable for the cabinet to deal with GANEFO’s request because of the highly political nature of the issue.
This study investigated the indigenousness of pelota mixteca, a ball game played in Oaxaca state, Mexico, focusing on the relationship between sports equipment and body techniques. One significant aspect of sports cultural studies is the study of sports techniques. The evolution of any given sport is accompanied by improvement and transformation of movement techniques and the invention of sports equipment. In early times, pelota mixteca players used their bare hands, as was the case in traditional European ball games. However, one man began to use a glove to protect his hand, and gradually other players came to adopt this practice. The glove was subsequently improved and its intended use changed from hand protection to hitting the ball harder. The ball was also modified so that it could fly further. These changes in equipment affected the body techniques used in the game. Before they began using a heavy glove and ball, it is quite likely that pelota mixteca players used the same hitting techniques as those seen in European ball games. After adopting the heavy glove and ball, the stroke style changed from swinging to punching or bouncing. These transformations in body techniques and sports equipment characterized the indigenousness of pelota mixteca.
This study was designed to compare the influences of walking, resistance exercise, and badminton, a game involving physical activity, on mood and heart rate variability (HRV). Forty-eight healthy young adults (23 women) performed submaximal strength tests and an incremental treadmill running test to determine peak oxygen consumption (VO2peak). On subsequent days, 4 counterbalanced interventions were done: 10 min of either walking, resistance exercise, badminton, or seated rest (control condition). Mood and HRV were measured before and after each intervention. As indices of mood, Pleasure and Arousal levels were measured using the Twodimensional Mood Scale. Power in the high-frequency range (HF) and the ratio of power in the low-frequency range (LF) and HF (LF/HF) were calculated as indices of HRV. Oxygen consumption (VO2) was monitored during each intervention. The influences of physical activity types on mood and HRV were analyzed by two-way repeated ANOVA using a Mixed model. Then, individual differences in mood change and HRV were estimated by intra-class correlation coefficients (ICC) calculated from the outputs of the Mixed model. The exercise intensities of the interventions were 45.2%VO2peak for walking, 41.3%VO2peak for resistance exercise, 74.3%VO2peak for badminton, and 9.9%VO2peak for seated rest. The results of ANOVA revealed that badminton increased the Pleasure level significantly in comparison with resistance exercise and seated rest (p ≤ .044). All exercise interventions significantly increased the Arousal level in comparison with seated rest (p < .001). For HRV, HF after badminton and resistance exercise was significantly lower than after seated rest; LF/HF after badminton and resistance exercise was significantly greater than after seated rest. No difference in HRV was found between brisk walking and seated rest. Although no individual differences (ICC ≤ 0.12) in HRV change were found, individual differences in mood change were evident. Individual differences in changes in the Pleasure level were especially large (ICC = 0.32) relative to those in changes in the Arousal level (ICC = 0.18). These results demonstrate that the effect of physical activity in the form of a game on pleasure mood is greater than for walking and resistance exercise, that physical activity of any type increases the arousal level, and that there are individual differences in the mood changes resulting from physical activity. However, no individual differences were found for HRV change, which tended to be influenced by the type of physical activity. Resistance exercise reduces parasympathetic nervous activity and activates the sympathetic nervous system to a greater degree than aerobic exercise.
The purpose of this research was to clarify the “technical training” activity actually employed by table tennis players, targeting world’s top-level women choppers. A survey was conducted using a semi-structured interview based on qualitative research focusing on the process by which players strengthened their skill. The subjects were 7 women choppers who were ranked within the world top 50 by the International Table Tennis Federation in February 2017. The results indicated that all of them had gone through a process in which, after they had become choppers, they made efforts to acquire “cut and push” skill at the first stage, after which there was a period of transformation in their style of play to one of attack. Finally, they made efforts to explore original playing techniques by confronting problems with their individual style. With regard to their current approach to individual problems, the following aspects were emphasized: 1. The importance of the early stage of a rally, from the serve to the 3rd or 4th ball; 2. The importance of a long rally, i.e. being able to hold out tenaciously; 3. The importance of an attack technique without a fixed idea, which is an approach hardly adopted by choppers; and 4. A playing style that considers players’ tasks and aptitudes, to make full use of reflections from games. Clarification of the overall picture of the strengthening process of top players may make it possible to devise individual training concepts by imaging their futures, suggesting the need to propose a new training activity.
This study was conducted with the aim of providing new viewpoints for observing the imitation movements of children during expressive play by demonstrating differences in the movement characteristics of 3 types of imitation: “Imitation of a framework”, “Exaggerated imitation”, and “Original imitation”. Thirty elementary school children improvised an imitation of an elephant (as presented visually in a picture) using their whole body as expressive play in a physical education class. The children’s movements during their improvised imitation were then analyzed in two steps. First, 3 highly experienced dance researchers qualitatively assessed and classified the imitation movements made by the children into 3 types. Then, quantitative assessment of the 3 characteristic imitation movements was performed using motion analysis, and the viewpoints for classifying them were extracted using decision tree analysis.
The viewpoints that were extracted to classify the types of imitation movement were “right hand movement”, “movement of the center of gravity”, “movement of the toes”, and “change in the angle of the trunk and head”. Based on these viewpoints, the features of the 3 types of imitation movement were determined. Although only “Imitation of a framework” had direct image movements (swinging of the arms) symbolizing the imitated object (i.e. the elephant’s trunk), it did not capture the texture of the imitated object, smaller movements of the central and terminal parts of the body being necessary. “Exaggerated imitation” had involved multiple direct image movements to represent the imitated object, and the children who adopted this approach moved dynamically from the center of the body, grasping the texture of the movement of the imitated object. “Original imitation” did not involve direct image movements of the imitated object, and instead the image had its own movements, moving from the center of the body with greater movement of the feet. These findings might be useful for classification of imitation movements and evaluation of improvisation in the expressive play of elementary school children during physical education class.
One of the most important factors for winning football matches is to score goals. At the field level, one important attack strategy is to use the gap between the opposing defender (DF) and midfielder (MF) (DFMF gap). An attack strategy using the DF-MF gap is one of the challenges of Japanese football, but little research on this strategy has been done and its effectiveness is currently unknown. In the present study, therefore, using notational game performance analysis, we aimed to clarify the effectiveness of attacks using the DF-MF gap, and the characteristics of this strategy in the J League (JL) and the German Bundesliga (BL). The sample consisted of a total of 20 games: 10 in the JL (2015 season) and 10 in the BL (2015/2016 season). For statistical analysis, independent t test and chi-squared tests were conducted. In both the JL and BL, it was observed that for attacks using the DF–MF gap, the frequencies of shots, penalty area intrusions, and scoring were higher than for side attacks, suggesting that attacks using the DF–MF gap were more effective. Furthermore, a lower ratio of attacks using the DF-MF gap was observed in the JL than in the BL. Also, the success rate of play in the DF-MF gap and the occurrence rate of play in a “forward” direction was significantly lower for the JL than for the BL. These observations suggest that the difference between the JL and BL lies in the frequency of attacks using the DF–MF gap and in play within it. One of the challenges for the JL is to increase the frequency of play that carries the ball forward into the DF–MF gap without losing possession, in order to increase the occurrence rate of play in that area, and eventually the success rate of attacks using the DF–MF gap.
In baseball batting, rotation around the long axis of the bat, know as " rolling ", has been observed. A batter who can attain a higher rolling speed before ball impact can achieve a higher rotation speed of the struck ball, which increases the ball’s flight distance. It has been suggested that batters who swing the bat with high nutation can attain a high rolling speed. The purpose of this study was to investigate the effect of instruction aimed at increasing the rolling speed in baseball batting. Ten batters performed tee-stand batting under 2 conditions: a usual swing (CON1), and a swing after being instructed to position the bat vertically, and then swing by rapidly lowering the bat head (CON2). The three-dimensional motion of the bat was measured using a small accelerometer and gyro sensor attached to the grip-end of the bat. This sensor was able to measure the swing speed, swing time, rolling speed, swing angle (angle between the bat head velocity vector and the horizontal plane) and vertical angle of the bat (angle between the long axis of the bat and the horizontal plane) before ball impact and the swing trajectory from the start of the swing until ball impact. The rolling speeds employed were 726°/s (CON1) and 854°/s (CON2). The rolling speed for CON2 was significantly higher than that for CON1 (p <0.05). On the other hand, there was no evident difference in swing speed between CON1 (30.1 m/s) and CON2 (30.2 m/s), nor were there any differences in other swing parameters before ball impact. Batters who swung the bat at a high nutation speed in response to instruction increased the rolling speed, but those who were unable to change the swing trajectory and nutation speed failed to change the rolling speed. These results indicate that batters increase the rolling speed without changing swing parameters such as swing speed, swing time and the vertical angle of the bat in response to the above instruction.
The present study was conducted to clarify the process by which students who do not attend school regain physicality through participation in a long-term camp used as an adventure education program. We looked at 8 non-attending students who participated in the long-term camp. We collected data by observing the participants and analyzed them using the Modified Grounded Theory Approach. The findings were as follows.
1)We found that in the process of regaining physicality, students went through 3 stages of “regaining a connection with the body”: ①“a sense of discomfort towards the body and physical manifestation of stress”, ② “awareness of the body” and “facing up to oneself through experience” by “experience of approaching physical limits”, and ③ “feeling confidence in the body”. 2) In terms of the factors that affect the recovery of physical confidence, we found that one factor was “connection with others and nature via the body”, which included 3 categories: “receptive involvement with staff via the body”, “peer relationships in an existential dimension through the body”, and “emotional experience based on physical sensations in nature”.
[Objective] Various methodologies have been employed for memory rehabilitation, such as environmental control, improvement of learning methods, compensatory strategy training, or group-based interventions based on the characteristics of the patients. In some cases, however, these approaches have been reported to be inappropriate for patients suffering from marked memory deficit. Therefore, new, more effective approaches for recovery of memory deficit are needed. Several previous studies have reported that physical activity and exercise can affect cognitive function. However, empirical evidence obtained from patients with memory deficit is still insufficient. The aim of this study was to clarify the effect of aerobic training on memory ability in a patient with memory deficit.
[Methods] The subject was a 48-year-old, right-handed male with memory deficit subsequent to hypoxic encephalopathy. We used an A-B-A single-case experimental design. The word delayed recall task and word fluency task were conducted 10 times in each phase. During the baseline A and washout A-phases, after memorizing 3 words, the subject performed a paper and pencil task for 15 minutes, and thereafter recalled the 3 memorized words and performed the word fluency task. During the B-phase, after memorizing 3 words, the subject pedaled a bicycle ergometer at 50W for 15 minutes, and thereafter performed the recall and word fluency tasks.
[Results] Average performance in the delayed recall task was 0±0 words in the baseline A-phase, 2.3±1.1 words in the B-phase, and 0.1±0.3 words in the washout A-phase (F(2,18)=37.098, p<0.0001). That in the word fluency task was 2.7±0.9 words in the baseline A-phase, 2.3±1.3 words in the B-phase, and 3.6±1.3 words in the washout A-phase.
[Discussion] These results suggest that aerobic training can lead to recovery of memory deficit. However, although we were able to observe acute effects, comprehensive recovery of cognitive function was not achieved, and the long-term effect was not tested. Further research is needed in this area.
The number of school teachers in Japan that take sick leave due to mental illness temporarily decreased below 5,000. However, it exceeded 5,000 after the academic year of 2013 and has remained at a high level since then. Different strategies that are optimal for individual teachers are required for improvement of their mental health, and one effective approach may be physical activity. The present study examined the influence of physical activity on the mental health of elementary school teachers. A questionnaire survey of full-time teachers (n=700) working in public schools was conducted using the General Health Questionnaire (GHQ28) and the International Physical Activity Questionnaire; Japanese version (IPAQ-Long Version). Valid responses (n=542) were analyzed using the Statistical Package for the Social Sciences. The participants included 187 men and 352 women ranging in age from 22-60 years (mean 42 years). The length of career as a full-time teacher (number of years after being first officially employed) was 0-39 years. The average period of teaching experience was 17.3 years. The level of mental health was assessed using the GHQ. The results indicated that 45.9% of the participants had some mental problems. Especially, scores for “somatic symptoms” were significantly higher in female teachers than in male teachers. The mean amount of total physical activity determined using the IPAQ-LV was 2,029.0 MET-minutes per week. Physical activity in the worksite accounted for approximately 50% of the total. In the context of “leisure”, the amount of physical activity for male teachers was significantly greater than for female teachers. Moreover, the influence of physical activity examined using multiple regression analysis confirmed a model for female teachers in which a significant pathway was identified from worksite physical activities to “somatic symptoms,” “anxiety and insomnia,” and “social dysfunction”. Furthermore, a significant pathway was identified from physical activity during housework and garden work to “social dysfunction”. This study reconfirmed the deterioration of mental health in elementary school teachers. The limits of this study and future issues including the investigation of confounding factors related to the results and the need for longitudinal research were also discussed.
The development of reforms covering extracurricular sport activities at school is one of the mostimportant issues facing sports administration in Japan. Several measures are being discussed to rectify theproblems identified with such sport activities. In particular, it has been suggested that relationships withcomprehensive community sport club activities should be built in order to alleviate the burden on teachers,enhance expertise in sport instruction, and create suitable sport conditions for individual students. In Japan,however, there are not many existing examples of good relationships between extracurricular sport activitiesand comprehensive community sport clubs, probably because of disparity between the intentions of sportadministrations and those of schools (faculty members).
In this research, we conducted an interview survey of 6 former supervisors who had been engaged in sportadministration at local government level. They also had experience of being in charge of extracurricular sportactivities as school teachers and working as staff members in charge of facilitating comprehensive communitysport clubs. Analysis of their statements helped to clarify opinions and attitudes of administrators concerning thedevelopment of comprehensive community sport club activities: (1) Through the facilitation of comprehensiveclubs, the former supervisors gained much awareness about their own sport instruction. (2) The former supervisorsrealized that sport administration faces many dilemmas within the educational administrative organizations towhich it belongs, thus revealing the structure of conflicts within those organizations. (3) Although they indeed hadpositive opinions about building good relationships between extracurricular sport activities and comprehensivecommunity sport club, the former supervisors became reluctant to realize such relationships after they resumedworking in schools.
From the above findings, we conclude that an attitude of reluctance to normalize reform and follow-up existswithin sport administration. It can also be said that reform of extracurricular sport activities in Japan will notoccur as long as the current system of sport administration and occupational culture is sustained. In Japanesesport administration including local governments, we should positively consider appointing private citizensthrough whom efforts should be made to change the consciousness of administrative officials and schools (facultymembers) .
The purpose of this study was to clarify methods for promotion of Olympic and Paralympic Education (OPE) from the viewpoint of teacher who was in charge of OPE that invited athletes as guest lecturer to school.
2 categories of difficulty in implementing OPE were recognized: “Trouble with administrative procedures” and “Preparation for good practice”. The effect of OPE was divided into 5 categories: “Improvement of interest”, “Improvement of moral values”, “Impact on life-style”, “Acquisition of knowledge” and “Acquisition of skills”. With regard to problems related to continuous implementation of OPE, 5 categories were recognized: “Preparation for effective practice”, “Early planning”, “Budgeting”, “Establishment of teacher in charge” and “Removing the teacher’s sense of resistance”. To address these actual issues, it was suggested that formulation of a system for cooperation between faculty members and lecturers, and for developing effective teaching methods would be useful.
However, as this research was based on a survey conducted on teacher who practiced OPE. It will be necessary to expand the survey to students who have received OPE, and to education committees that can connect teachers in charge of OPE and lecturers with Olympic and Paralympic athletes who have acted as lecturers. From these perspectives, it will be necessary to consider how OPE can be promoted.
The purpose of this study was to clarify and overview the current status of all colleges and universities (hereinafter, CUs) in Japan offering physical education courses as a component of liberal arts in higher education (hereinafter, PE in higher education) since the first complete survey that was conducted in 2000. Out of the 775 CUs existing as of August 2016, 742 CUs excluding 24 graduate universities and nine PE colleges were included in the survey. The following five items of information were extracted on PE in higher education from the CUs rules，handbook for students and syllabus posted on each CU website: 1) present/not present, 2) course type, 3) compulsory/optional, 4) number of compulsory credits, and 5) integrated title of the courses group. Among the 742 CUs surveyed, 97.7% (725 CUs) offered PE in higher education, except for 17 CUs (2.3%) that did not offer PE in higher education. The 725 CUs offering PE in higher education were categorized into courses comprising mainly practical skills (98.2%; 712 CUs), lectures (63.4%; 460 CUs) and compulsory for all departments (28.0%; 203 CUs), and compulsory for some departments (40.8%; 296 CUs) including practical skills (94.6%; 280 CUs), lectures (31.1% ; 92 CUs), and practical skills and lectures (25.7%; 76 CUs) in undergraduate departments. The number of PE in higher education credits offered as compulsory subjects was 2.15 ± 0.84 (mean ± standard deviation) and 0.5 to 5.0 (minimum - maximum) credits. The terms included in the integrated titles of PE in higher education courses for 725 CUs offering such courses were “Sports” (42.8%; 310 CUs), “Physical education” (39.9%; 289 CUs), “Health” (37.8%; 274 CUs), “Health education” (18.6%; 135 CUs), “Health and physical education” (17.8%; 129 CUs), and “Science” (14.8%; 107 CUs). The results revealed that PE in higher education was offered at approximately 98% of all CUs in Japan, and that the courses were compulsory at approximately 40% of them. Therefore, it can be said that PE in higher education is currently being offered at most CUs. This study has provided an overview of PE in higher education in Japan for the first time since 2000. Future research will involve conducting current status surveys of the curriculum contents focusing on the educational system for PE．
The purpose of this study was to clarify the nature of the “tairyoku（bodily power）issue” during the period after World War II to the 1950s through analysis of newspaper articles published at the time.
Soon after World War II, the issue of taii, as assessed in terms of height, weight and chest circumference, was identified in children. A hange from a decrease to an increase occurred in 1948, based on comparison with records obtained before the war. It was also assumed that tairyoku could be regarded as an index of post-war recovery, reflecting the increase of taii in children. At the end of the 1940s, the tairyoku problem was thought to have been due to lack of nutrition during the war. Therefore, it was concluded that improved nutrition and rest for children would be the solution.
In the 1950s, the tairyoku issue in Japanese athletes also emerged after the poor performance of the Japan team in the Helsinki Olympics, and this was extended to an interpretation that a “tairyoku problem” existed in the Japanese nation as a whole as a result of wartime privation. However, in the mid 1950s, the notion of the physical ideal evident in the West was held in sharp contrast to the statistics obtained in Japan immediately after the war. Thus, tairyoku was considered to be a functional index of modernization.
These circumstances illustrate that in the process of post-war reconstruction, the “tairyoku issue” was always problematic because it was based on criteria that were representative of that era.