The purpose of this study was to obtain qualitative knowledge regarding the effective punts in rugby union by using an embedded model of mixed methods. In previous research, punts in the last 20 min; punts past own team’s 22m area; punts in Turnover, Restart, and Quick tap; punts in 1 ruck/ mauls; and punts in Scrum Half were significantly different between the Winning Team and Losing Team. For better interpretation of these results and further analysis for this qualitative research, a semi-structured interview was conducted with two elite Japanese players. The systematic cause analysis technique was used to analyze the data.

Our findings were as follows:

・Winning Team could use Area kick, Grubber kick, and Kick pass past their own 22m area.

・High accuracy of the Long kick is one of characteristics of players in the Winning Team.

・Punts by team tactics would be effective in the Restart situation.

・A dominance at an attacking gain line in the opponent’s area provides players an opportunity to use punts in Scrum Half.

These findings contribute to the practical knowledge regarding punts and could be useful for players and coaches.

Anthropometric characteristics have been considered as useful indicators for athletic performance in rugby. However, there has been no detailed report on anthropometric characteristics of Japanese college rugby players. The purpose of this study was therefore to investigate differences in anthropometric characteristics of college rugby players who participate in different competition levels. A total of 101 players that consist of 49 forwards (FWs: aged 20.4±1.4 years old, 10±3.5 years of participation) and 52 backs (BKs: aged 19.8±1.3 years old, 11.5±4.0 years of participation) from a college rugby team participated the study. Participants were categorized into official competition members (Sr) (19 FWs and 20 BKs) and the rest (Jr) (30 FWs and 32 BKs). Anthropometry using the ISAK protocol (stature, body mass and eight skinfolds) and a body composition assessment using the underwater weighing (UWW) were conducted. Anthropometric indices (sum of upper limb skinfolds [US], sum of trunk region skinfolds[TS], sum of lower limb skinfolds [LS], sum of eight skinfolds [Σ8SF], body mass index [BMI] and lean mass index [LMI] were calculated from anthropometry while a percentage body fat [%FAT] and lean body mass [LBM] were estimated from the UWW. Both FWs and BKs showed significant differences in stature, US, LS, Σ8SF, LMI, and LBM between Sr and Jr players (p<0.05). In addition, JrBKs had significantly (p<0.05) greater %FAT compared with Sr BKs. The present study revealed differences in anthropometric characteristics in college rugby players of different competition levels.

Conditioning for injury prevention in soccer is important because of the high number of injuries. Many previous studies have focused solely on physical problems or solely on psychological problems. In this study, multiple factors were considered to gain a better understanding of the physical and psychological status of athletes. The current injury, current pain, ankle instability, fundamental pattern of movement, catastrophic thoughts of pain, daytime sleepiness, sleep dysfunction, and symptoms of anxiety and depression of Japanese male college soccer players were assessed. Among the 122 collegiate soccer players who completed all questionnaires and measurements, 43% experienced pain, 27% had injuries, 50% had ankle instability, 21% were restricted in their fundamental patterns of movement, 20% had catastrophic thoughts of pain, 48% experienced daytime sleepiness, 20% experienced sleep dysfunction, and 14% experienced symptoms of anxiety and depression. Only 11% of the athletes showed no physical or psychological problems. Eighty-nine percent had either a psychological or physical problem, and almost half of the cohort (48%) experienced both physical and psychological problems. This study demonstrated how difficult it is for athletes to reach their peak condition, as factors other than ‘skill’ also play a role in conditioning. Assessment of both physical and psychological aspects is needed to understand the conditioning status of athletes.

This study aimed to recommend the energy and protein requirements on general training and match days for Japanese male senior high school soccer players. Seven players were surveyed and measured during two consecutive days of training (training group). Nine players were surveyed and measured during two consecutive days of expeditions (match group). The recommended energy intake (EI) was estimated using total energy expenditure (TEE) measured by Misfit Shine, a triaxial acceleration sensor-mounted activity meter. The recommended protein intake was estimated using measured values obtained by the nitrogen balance (NBAL) method. Results suggested that EI should be 48–52 kcal/kg/day on training days and 49–54 kcal/kg/day on match days. Results also suggested that protein intake should be 0.8–1.5 g/kg/day on training days and 1.4–2.4 g/kg/day on match days. Moreover, we believe that the recommended energy and protein intake for Japanese male senior high school soccer players on match days should be higher than on training days.

This study aimed to examine the relationship between thigh muscle glycogen consumption and recovery kinetics using ¹³C magnetic resonance spectroscopy (MRS) in semi-professional soccer players. Four male semi-professional soccer players participated in this study. Muscle glycogen levels were measured using ¹³C MRS before (Pre), within 2 h after the game (Post), 24 h after (A24h), and 48 h after (A48h) the Post. The rate of decrease in muscle glycogen levels tended to increase as high-intensity running distance ( > 13 km · h^-1; HIR) increased during the match. The recovery kinetics of muscle glycogen levels showed a strongly negative correlation with HIR (r=- 1.00, p<0.05), and a moderately negative correlation with the total distance covered (TD) (r=-0.73, p>0.05) at A24h. Despite the small number of subjects, these results suggested that muscle glycogen consumption and recovery kinetics were affected by game performance, particularly HIR. Thus, these data could be beneficial as baseline data when planning an individualized recovery strategy after the match with taking into consideration of the match's external load.

The aim of this study was to analyze the sprinting characteristics of female soccer players during matches using the global positioning system (GPS) device method combined with video analysis software. Eighteen Japanese collegiate female soccer players (age: 20.3 ± 1.3 years; height: 161.1 ± 5.7 cm; body mass: 55.6 ± 6.2 kg) were equipped with GPS (10 Hz), and sprinting (> 21 km/ h) data during eight official matches was analyzed. Using video cameras, all games were filmed to record the situations when players were sprinting. The videos linked GPS data with the dedicated analysis software, and the data was extracted from the videos. We analyzed 790 samples of sprinting according to ball possession, play situation, and running direction for each playing position. The total number of sprints per match was 98.8 ± 11.2. The total number of sprints per match for each position was 26.7 ± 4.7 for forward, 30.4 ± 6.2 for side midfielder, 10.1 ± 3.9 for central midfielder, 18.6 ± 6.2 for side back, and 12.9 ± 2.1 for center back. The results of the chi-square test showed that the sprinting demonstrated during the game at each position depended on the situation. Our findings suggested that the characteristics of sprinting of Japanese collegiate female soccer players during a match differed depending on the situation and position the players faced.

The purpose of this study was to identify latent subgroups with respect to defensive transition plays from an achievement pattern data of the defensive transition in the professional soccer game. The research procedure comprised two steps, 1) an analysis of achievement criteria of the defensive transition items by a decision tree analysis, 2) an analysis of latent classes of defensive transitions by latent class analysis (LCA). The 158 defensive transitions in two games of the J-league in 2016 were used. An achievement pattern data of nine defensive transition items consisted of approach, press, and DFL control were used for LCA. Three latent classes, class 1: High achieved transition play (HA), class 3: Moderate achieved transition play (MA), and class 2: Low achieved transition play (LA) were identified. HA (54.25±5.35) showed significantly higher defensive transition skill (DTS) score compared with MA (42.61±5.10) and LA (27.85±3.24), and MA showed significantly higher defensive transition score than LA (p < 0.05). In addition, the relationship between LA and the opponent PA entry was found. These results indicated that LA allowed the opponent counter attack leading to failure of defensive transition play. In conclusion, this study successfully identifies latent classes of defensive transition plays by LCA.

The purpose of this study was to clarify physical activity characteristics of the soccer kids program (Japan Football Association recommended program) by comparing with typical daily activities in nursery school children. In particular, we focused on the differences among individuals and nursery schools. The subjects were 38 children in the 5-year-old class and 29 children in the 4-year-old class in nursery schools. Physical activity (moderate-to-vigorous physical activity : MVPA and step counts) was measured by using a uniaxial accelerometer (Lifecorder EX; Suzuken Co. Ltd, Nagoya, Japan). The physical activity measurement was performed for 3 days (from 9:00 to 12:00) of “usual school day”, “outdoor activity day”, and “soccer class day”. As the results of repeated ANOVA, physical activity of the soccer class day was significantly higher than other days, and physical activity of the usual school day was significantly lowest in the 5-years class (p<0.05). The coefficient of variation (CV) values of physical activity during the soccer class day were the lowest compared to other days in both classes. One-way A NOVAs showed there were no significant differences between nursery schools in physical activity during the soccer kids program. Our findings suggest that the soccer kids’ program has an effect on increasing physical activity a day in nursery school children, and the program may also increase physical activity of those who are not active in the outdoor activity program.

This investigation primarily aimed to quantify the movement profiles of soccer matches according to playing positions and tactical formations in the Japanese professional football league using the global navigation satellite system (GNSS). Over three years, 758 observations were obtained from 125 official matches of the second division of the Japanese professional football league. Data were integrated into tactical formations and playing positions. Match activity was assessed by the validating GNSS (OptimEye X4; Catapult Sports). Furthermore, the duration and distance of activities at different speed thresholds (>19.8, >24, and 19.8-24 km/h) were assessed. The duration and distance of activities at all speed thresholds significantly differed with respect to tactical formations and playing positions (p<0.05). Significant interactions between tactical formations and playing positions were identified when the total distance and distance at 19.8-24 km/h threshold were assessed (p<0.05). Additionally, the 3-5-2 tactical system and central defender playing position significantly differed from the other systems and positions (p<0.05). A shorter distance in the central defender playing position and a longer distance in the 3-5-2 tactical formation were significantly different features in match movement characteristics in the Japanese professional football league.