Many recent studies have investigated talent identification in soccer players; however, no clear results have been reported due to the lack of prospective research designs. Moreover, the issue is complicated by large differences in individual biological maturation rates. The present study investigated the index of talent identifi cation for youth soccer players in career development. Sixty-two adolescent soccer players participated in this study. They were divided into professional, collegiate, and regional players based on their performance level at 18 years of age. Height, weight, skeletal age, stepping speed, endurance, and choice reaction time (hand: HRT, foot: FRT and hand-foot-complex: CRT) were measured. CRT was signifi cantly faster in professional players and collegiate players compared with regional players. The mean values of body weight, height, and CRT tended to be higher for professional players than collegiate players, albeit statistically insignificant. Our findings suggest that adolescent soccer players with faster CRT should be identified as potential professional players.

This study examined the objective assessment of 6 aspects of physical fitness of referees. The first experiment assessed Japan football association (JFA) referees. We measured distance of movement, speed of movement, heart rate and distance of movement out of the diagonal system of control. The second experiment assessed both international-level referees and JFA referees. We measured distance from the points where fouls occurred to where the referee stood.

Results revealed significant differences between Class 1 and Class 2 JFA referees in distance moved outside the diagonal system of control. Moreover a significant difference was found between international-level and JFA referees as to distance from points where fouls occurred to where the referees stood.

Referees were assessed by distance of movement, distance from points where fouls occurred to where the referees stood, and heart rate. Speed and distance of movement out of the diagonal system of control may be new criteria to evaluate referees objectively.

It is widely recognized that sports teams have a “home-team advantage”. Despite its acknowledged importance, there is a lack of research on this phenomenon, specifically in the context of professional sports in Japan. The purpose of this study is to examine the influence of crowd density (the ratio of attendance to seating capacity) and spectator attendance (the total number of spectators attending home games in the current season) on home-team advantage in the J. League. The relationship between crowd density and hometeam advantage was examined by an assessment of correlation coefficients. The relationship between team performance and stadium usage patterns was also investigated through a series of chi-square tests. Results showed that clubs which primarily use their main stadium for home games do not necessarily have a high crowd density, while other clubs have a higher level of crowd density by using several stadiums. In addition, the results indicate that crowd density has a weak effect on the home-team advantage. Based on the study findings, the findings, managerial implications and directions for future research are discussed.