The purpose of this study was to investigate the effect of the mass and position of the center of gravity of a baseball bat on its hitting performance. Twelve skilled baseball players were used in the study. A bat was developed for which the mass (869.2 - 912.4 g) and position of center of gravity (30.1 - 32.8 cm : the distance from bat head) could be adjusted. In this experiment nine different settings for the position of the center of gravity and the mass were used. The motion of the bat during swings was analyzed by the three-dimensional direct linear transformation method using two cameras, and kinematic data were calculated for the moment of impact of the bat with the ball and also for the entire hitting process. The main results are summarized as follows:
1) The head velocity was greater when the subjects swung a baseball bat with the center of mass located near the grip than when they swung another baseball bat with the center of mass located far from the grip.
2) For all the baseball players, the bat′s mass did not affect the head velocity of the bat at impact.
3) The head velocity was greater when the subjects swung a baseball bat with a larger moment of inertia about the axis passing through the grip than when they swung another baseball bat with a smaller moment of inertia.
4) In some cases, the mass of the bat had a significant influence on the angular velocity on impact for a player who had a translational swing. In this case, the characteristic of the swing type was shown to affect hitting performance.
    When choosing a suitable bat for each player, the swing style of the player needs to be considered. This finding suggests that when characterizing bats, not only should the mass of the bat and the position of its center of gravity be used as indexes, but also the moment of inertia, which is related to the grip of the bat, should be employed.

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    Batters often get injured when hit by a pitch. In particular, a hit on the face or the head is extremely dangerous; therefore, the batter is obligated to wear a helmet. A baseball helmet is an important protective gear to prevent a head injury when hit by a pitch. Although the shock absorption performance of a helmet has been evaluated, the change in its impact performance when hit repeatedly has not yet been considered. This is because once a helmet receives a large impact, it is not supposed to be re-used, even if there is no visible damage to its surface. However, if the damage is not visible, there is a possibility that the damaged helmet is re-used.
    In this study, a baseball ball launcher was built, and a repeat impact experiment was conducted using a ball and a head model with a helmet. The effect of the number of impacts on the acceleration of the head model was considered. When the helmet received a large impact, such that the liner material of the helmet was damaged, the acceleration of the head model was increased remarkably in subsequent impacts. Therefore, it was found that the acceleration was transmitted to the head model since the helmet was not able to absorb the impact energy of the ball after the liner material was damaged.

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    Skeleton is a winter sport in which competitors aim to drive a one-person sled in a prone, head-first position down an ice track in the fastest time. Top speeds attained in skeleton are approximately 130 km/h. But studies of skeleton have not been carried out until now. The purposes of this study were to measure the dynamic strain, the vertical acceleration and the horizontal acceleration applied to the sled frame, and try to construct a feedback system for athletes.
    The experiments were carried out at the Spiral. In the experiment, first a strain gage and an acceleration transducer were attached to the frame, then data was collected with a compact recorder.
    The results are summarized as follows.
·Measuring acceleration and strain for result, it is possible to give the athletes feedback on data.
·Vertical acceleration was 2-4G, greater than horizontal acceleration. Horizontal acceleration was 1-2G at curve.

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    The purpose of this study was to estimate the distance decay parameters of J-League season ticket purchase rate, and to clarify the relationship between the distance decay parameters and population densities/competition of catchment areas. The total number of the sample was 53,727 which came from the season ticket holders of 20 J-League clubs in 2007. The distance and the population were calculated by using Geographic Information System. The findings of the analyses are summarized as follows;
    A gradually weakening relationship between J-League season ticket purchase rate and distance from stadium was observed. Also it was shown that the distance factor has an effect on the J-League season ticket purchase rate. The distance decay rate of densely populated area is low (distance decay slope is gentle) , while the distance decay rate of thinly populated area is high (distance decay slope is steep) . The catchment areas of J-league season ticket compete with other clubs′ catchment areas in the densely populated regions. That is to say the spatial demand, which is the distance decay rate of J-League season tickets, is affected by the difference of city size and the existence of other competing clubs.

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BACKGROUND : Although enhancement of interest in physical activity and exercise (PAE) is one of the important issues for health promotion, effective strategies have not been established. The application of the concept of the gateway would be useful for developing these strategies.
PURPOSE : The purpose of this study was to examine the associations between interest in health behavior and leisure activity interest in physical activity and exercise.
METHODS : The respondents were 1,103 Japanese adults (39.8±10.1years) recruited from the registrants of a Japanese social research company. The study was a cross-sectional study, using an internet-based questionnaire. Data were collected in December 2008. We analyzed the data from those in Precontemplation and Contemplation groups regarding stages of change for exercise behavior (N=583, 52.9%) . Among the research items, the dependent variable was contemplation. Independent variables included interests in 14 sports activities, 11 health behaviors, and 28 leisure activities. All data were stratified by gender (male or female) and age groups (20-39 years or 40-59 years) . Path analysis was utilized for examining the predictors of contemplation.
RESULTS : Path analysis revealed that interest in driving a car or bike in males aged 40-59 years, interest in music and restriction of food intake in females aged 20-39 years, and interest in watching sports in females aged 40-59 years were directly predicted by contemplation stage for exercise behavior, as well as interest regarding PAE.
CONCLUSIONS : These results indicate that in addition to health behavior, leisure activity could play a role as the gateway for interest in physical activity and exercise.

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    The top professional football league of Japan, the J. League Division 1 (J1) currently consists of 18 clubs. Each club is scheduled to play matches with the other 17 clubs at home and away stadiums, with a total of 34 games per year.
    Compared to the multiple clubs based in the Kanto district, the Chugoku and Kyushu districts only have a single club each. This condition increases the sparsely organized clubs′ total burden of annual traveling for away games. This is due to the condition that the clubs return to their home town after each game and then travel again to the next away game even if they are scheduled for continuous away games.
    With the kick off time set at 6 p.m. for the games played during the Golden Week holidays and summer season, the clubs are required to secure after-game accommodation at the site when playing at away games located at a distance from their home town.
    In this research, information about the constraints currently applied for scheduling the games was obtained with cooperation from the J. League Association. We then interviewed the players, staffs and supporters of various teams and acquired the requests for scheduling the games.
    Based on our survey, we propose a scheduling procedure for the J1 League game that satisfies the fundamental and additional constraints considered by the J. League Association and the requests from the players, staffs and supporters. Finally, the schedule generated from the proposed study is compared with the actual 2007 J1 schedule, for discussion.

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    The purpose of this paper is to describe the building of a members′ usage analysis system of a fitness club using Visual Basic and to apply this system to a fitness club located next to a major terminal station in the Tokyo metropolitan area.
    The obtained data were in-out time records of the members of the club from April 2003 through March 2004, as well as its membership list. The daily usage data included date, clock-in time, clock-out time and membership number. The membership list included membership number, home address, type of membership, gender and age. The number of members for the club was over eight thousand. The annual cumulative number of users was approximately half a million. Monthly frequency in use for each member was calculated.
    The findings of the analysis are summarized as follows :
1.The analysis system was proved to be effective in cleaning and sorting out the enormous quantity of usage data.
2.Much the same relationships approximated by exponential function were observed between frequency in usage and number of users for any month throughout the year.
3.The extremely high coefficient of determination indicated that the frequency in use and the number of users were highly correlated.
4.The linear expression model was statistically useful for the prediction of the number of users.

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    After the collapse of Japan′s “bubble economy” , many golf courses went bankrupt because of a lack of redemption money for membership. Therefore, there were many trials between the golf courses and their members related to the redemption. This research aimed to present one of the solutions to the problem of the membership redemption, using an experiment based on the ultimatum game.
    The ultimatum game is often used in experimental economics. There are two players who do not know each other. They negotiate how to divide a windfall ; e.g. player #1 proposes how to divide the sum of the windfall between themselves, and player #2 can either accept or reject this proposal. If player #2 rejects the proposal, neither player receives anything. If player #2 accepts the proposal, both players receive money according to the proposal. This is one type of the bargaining games.
    In this experiment, undergraduate students as subjects took the roles of the golf course owners and their members. This experiment compared the negotiation processes of the two groups with either their information disclosed or not, with regard to the financial conditions of the golf course. The results of this experiment indicated that asymmetric information influenced the negotiation between the golf course owners and their members. The members showed a tendency to be satisfied with a 30%-40% redemption from the golf course owners.

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    The purpose of this research was to establish a model to quantitatively capture the changes in time series of a domestic public opinion toward the Japanese representative athletes in international sports events for the top athlete management. The Beijing Olympics, held in August 2008, was thought to offer one of the best cases to carry out this approach. As a result, extracting six evaluation patterns by comparing the social involvement levels between opening and closing of the Olympic games has been succeeded. The theoretical novelty of this research extends the Expectaion-Confirmation/Disconfirmation Model from a “consumer” analysis to a Japanese “society” analysis.
    The six evaluation patterns are: 1.Excessive Expectation type, 2.Preceded Expectation type, 3.Predetermined Harmony type, 4.Perfect type, 5.Satisfied after Viewing type, and 6. Impressed after Viewing type. The following findings were obtained from considerations of the results above. Among athletes with high performance, their expectations are high (Type 1) . Sports without highly expected players might face industrial reduction in the future (Type 2) . There are peculiar evaluation aspects in regard to female athletes (Type 3) . The scarcity of athletes who have both high expectations and good results (Type 4) . The difficulty of continuing social involvement for athletes (Type 5) . The possibility of expanding social involvement rapidly, and the problems of concentrating social concern towards particular players (Type 6) .
    Thus, the effectiveness of the Social Expectation-Confirmation/Disconfirmation Model has been shown. However, this result might be a special case limited to the 2008 Beijing Olympics. Our future task is to apply this method to other Olympic games including the winter games and other international games. This is because it is necessary to accumulate a large number of cases in order to improve the method generally.

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    From April, 2008, health check ups and health guidance (HCHG) have been provided to insured individuals between the ages of 40 and 74 by health insurance providers. The purpose of this study was to determine the awareness level of HCHG and identify its relationship to exercise behavior. The 816 respondents were above the age of 40 (male : n=402, female : n=414, 50.4±7.9 years) and obtained from the registrants of a Japanese social research company. The study design was a cross-sectional survey using an internet questionnaire. Logistic regression analysis was utilized. Awareness of the HCHG was 48.3% and that of Metabolic Syndrome was 97.2% of the sample. The Higher level awareness of HCHG was significantly correlated with exercise behavior (OR=1.57, 95%CI=1.15-2.14) . There was, however, no significant relationship between awareness of MS and exercise behavior (OR=1.59, 95%CI=0.67-3.76) . A promotion strategy for enhancing awareness of HCHG will be needed.

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Objective This study aimed to estimate the prevalence of walking behavior and investigate demographic correlates of recommended physical activity levels with five domains (exercise, commuting, working, shopping, and other movement) of walking behavior among Japanese adults aged 30-49.
Methods The sample was 5,009 Japanese adults collected from the registrants of a Japanese social research company. The study design was a cross-sectional study using an Internet questionnaire. The dependent variable was meeting physical activity recommendation levels (more than 150 min/1week) . Independent variables were demographic variables (e.g., gender, age, educational level, household income level, hour per day with TV watching, and hour per day with internet usage) . Logistic regression analysis was utilized.
Results Of all participants, 45.5% of men and 44.8% of women met physical activity recommendations. Regardless of meeting recommended physical activity levels, they walked for exercise less than 20%. The characteristics of those who met the recommendation levels were higher education, long Internet use and having a small number of children for men, and higher education, higher income and having a small number of children for women. As compared with those who did not meet physical activity recommendations, in lifestyle time men walked for shopping and other movement and women walked for shopping.
Conclusion Commuting and shopping for men and shopping for women were identified as a key factor for increasing walking behavior. It would be necessary for women to develop an intervention program which considers demographic factors such as marital status, employment status and household children.

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    The purpose of this study was to clarify the geographic distribution of public sports center users with regard to the distance decay model, and to verify the difference of the parameters of the use frequency level. The findings of the analyses are summarized as follows ;
    A logarithmic relationship was observed between the distance from sports center and number of users (R²=.572) . This suggests that the distribution of public sports center users is affected by the distance.
    And the distance decay parameter of low frequency users is much smaller than that of high and middle frequency users. This suggests that there is a possibility that users who live a short distance from the sports center would be higher frequency users than those who live a long distance from the sports center.

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    The Local Authority Act of Japan, revised in September 2003, aimed to reduce costs for public services and to enrich public service quality. As a result of the Act, all local authorities had to introduce CCT for public sports facilities by September 2006. The aim of this research was to clarify the change in customer satisfaction of a sports facility before and after the introduction of CCT using one facility in Japan as a case study, and to compare some performance data before and after the introduction of CCT. The data before CCT were collected in February 2006 and the post-CCT data were collected in February 2007 and 2008. Random sampling of respondents was used in those years. In total, 377 respondents in 2006, 587 respondents in 2007 and 457 respondents in 2008 were asked to complete the questionnaire after their activity. Some of the mean scores of users′ satisfaction were significantly higher than those recorded before CCT. However, the satisfaction of “Number of people in the pool” , and “Number of people in the activity spaces” in 2007 was significantly lower than satisfaction in two categories in 2006. The mean scores of “Overall satisfaction” of users in 2007 were significantly lower than those in 2006, but after that they recovered in 2008.

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