This report outlines the role of the trainer for the Japan national blind football team and the efforts made to qualify for the Paris 2024 Paralympic Games. In particular, we provided injury first aid, rehabilitation, injury prevention, weight training support, balance training, and coordination training to help the athletes improve their performance. Furthermore, during the Paris 2024 Paralympic Games, we treated the injuries, managed condition of the athletes, and prepared for the heat.

At the Paris 2024 Olympics, the Japan Men’s National Handball Team secured automatic qualification to the Olympic Games for the first time in last 36 years. Despite a demanding schedule from pre-tournament training camps to the conclusion of the competition, the team competed strongly against top European nations and successfully completed the tournament without any withdrawals due to illness or injury. This report provides an overview of the team’s journey from the Tokyo Olympics to securing qualification for Paris 2024, as well as the activities conducted during the Olympic Games.

Since the Tokyo 2020 Olympics, the Japan swimming conditioning team clarified the division of roles by qualification and continued the trainer support system with gender balance. In addition, the team worked on preventive measures for swimming shoulder and was able to enter the competition with some success. Since the finals of the Paris Olympics started as late as 8:30 p.m., two trainers from within the village and two trainers from outside the village worked together to provide late-night support. The competition suggested new challenges for our national team trainers, such as working with personal trainers in the future.

This study aimed to examine the effects of an intervention for Active Straight Leg Raise (ASLR) with pre-contraction of the core on kinetic chain disruption. This randomized control trial included 74 healthy adult males. We measured ASLR and Passive Straight Leg Raise (PSLR) angles pre- and post-intervention. The intervention group performed the ASLR intervention with pre-contraction of the core, while the control group rested for 5 minutes. Participants were divided into two groups randomly, and the examiners were blinded. If the difference between PSLR and ASLR was greater than 10 degrees, the participant was considered to have a disrupted kinetic chain. A two-way repeated measures analysis of variance was used to compare SLR angles pre- and post-intervention. Thirty-two of the 74 participants were determined to have a disrupted kinetic chain. ASLR in the intervention group increased significantly pre- and post-intervention. Intervention to promote spare contraction of the core improved ASLR and is expected to be applied to rehabilitation and prevention of sports trauma and injury.

The purpose of this study was to assess the impact of the COVID-19 pandemic-induced activity suspensions on injuries among male university football players during the course of the 2020 and 2021 seasons (affected by COVID-19) compared with the course of the 2019 season (a normal season). The incidence of injury was significantly lower in 2020 (1.10/1000 PH) whereas it was significantly higher in 2021 (7.28/1000 PH) in comparison to 2019 (3.62/1000 PH) the course of the pre-season period. The injury burden was significantly decreased in 2020 compared to 2019, while injuries by location showed a marked increase in 2021, particularly at the thigh. The duration of activity suspension and followed by the subsequent rapid increase in workload during the course of the pre-season may have contributed to the incidence and patterns of injuries.

For baseball players, bat swing velocity (SV) is one of the important factors. In previous studies, the medicine ball back throw (MBBT), medicine ball side throw (MBST), fat fee mass and grip strength have each been reported as index associated with SV. However, the best factors that influence SV are not clear. The purpose of this study is to clarify the relationship between SV, height, body mass, fat free mass index (FFMI), MBBT, MBST and hand grip strength in collegiate male baseball players using multiple regression analysis. Measurements were performed on 63 collegiate male baseball players on two separate days; height, body mass, FFMI, SV and grip strength were measured on day 1, and MBBT and MBST were measured on day 2. The results of this study showed significant correlations with SV in all index (p < 0.05). Multiple regression analysis was performed using the index for which significant correlations were found, height (p = 0.035), FFMI (p = 0.036) and MBBT (p = 0.005) were strongly associated with SV, suggesting that they are useful morphometrics and field tests, as well as important factors for increasing SV. The multiple regression equation to predict SV (Y) was Y = -9.133+0.396 × Height-0.077 × Body mass + 1.904 × FFMI + 0.014 × MBBT + 0.002 × MBST -0.067 × Grip strength, giving a coefficient of determination of 0.493.

In handball, many players apply resin or double-sided adhesive tapes to their palms and fingers to enhance handling. Ball grip strength, an indicator of ball handling, improves when using resin or grip tape compared to when using bare hands. However, no studies have compared the effects of the resin and grip tape. Additionally, despite the potential correlation between ball grip strength and handling capacity (HC), and the known influence of palm and finger size on grip strength, studies comparing HC between the sexes remain limited. Therefore, this study examined the relationship between ball-HC and grip strength by comparing the following conditions in male and female collegiate handball players: (i) bare hands, (ii) resin, and (iii) double-sided adhesive tape. A significant positive correlation between HC and ball grip strength was found in female players, but not in male players. Ball grip strength was the highest with double-sided adhesive tape for both sexes compared to bare hands. In addition, female players had greater ball-grip strength with resin than with bare hands. These findings suggest that the effects of different hand surfaces should be considered separately in male and female players.

In this study, we examined the relationship between changes in the height of medial longitudinal arch (MLA) of the foot after 5 km running and changes in toe flexor strength and running-induced changes in MLA height in healthy male university students. As a result, the navicular height and the arch height ratio decreased after 5 km running, and a significant positive correlation (r＝0.48) was found between the strength of the toe flexor strength and the amount of change in the arch height ratio before and after running. This suggests that it is important to prevent a decrease in MLA even for relatively short running distances of 5 km in order to prevent running-related injury. In the future, it will be necessary to investigate the effects of training aimed at improving foot function on the decrease in MLA caused by running.

This study aimed to determine the effect of foam rolling (FR) on maximum muscle strength on the intervention and non-intervention sides. The participants were 18 healthy adults. Here, maximum muscle strength was defined as grip strength and measured at baseline, pre-intervention, and post-intervention. Grip strength was measured in one set with the dominant and non-dominant hands. Grip strength measurements were performed in triplicate. Statistical analysis used the maximum value of three measurements. FR was applied to the forearm flexors of the non-dominant hand. The intervention was performed for 30 s in triplicate, with a 30 s rest between sets. No significant difference was observed between the baseline and pre-intervention values in either the intervention or non-intervention groups. Conversely, post-intervention values were significantly lower than at baseline and pre-intervention values. FR may reduce the maximum muscle strength of the intervention and non-intervention sides.

This study compared the effects of vibration foam rolling and static stretching (sleeper stretch) interventions on the range of motion of shoulder internal rotation, finger vertebral distance, and shoulder external rotation strength over time. A randomized crossover design was used with 14 healthy male college students in the two conditions. The results showed that sleeper stretch and vibration foam rolling interventions for 90 seconds significantly improved shoulder internal rotation range of motion and finger vertebral distance immediately after the intervention and 15 minutes after the intervention compared to before the intervention (P < 0.05). In contrast, shoulder external rotation muscle strength was significantly lower in the sleeper stretch intervention group than in the vibration foam rolling intervention group immediately after the intervention (P < 0.05). The results suggest that a 90-second vibration foam rolling intervention may improve shoulder internal rotation range of motion and finger vertebral distance without negatively affecting shoulder external rotation muscle strength.

Athletes on club youth team lead very busy lives, which often limits their ability to secure adequate sleep. Sleep education is said to be effective for conditioning such athletes. The purpose of this study was to examine the effects of in-season sleep education on sleep habits, body composition, and performance among female high-school athletes on club youth team. The results showed that sleep education significantly improved subjective sleep habits. Regarding body composition, there were significant decreases in fat volume, BMI, and body fat percentage. Sleep education increased the athletes’ awareness of the importance and potentially affect their conditioning.

The purpose of this study was to conduct basic life support (BLS) training with situation-based training (SIBT) and to identify student learning and challenges through SIBT. The results showed that the students became agitated and nervous, and were unable to promptly call for emergency medical assistance or an AED. In addition, challenges in operating the AED, requesting cooperation, and cooperating with others were identified, and the students learned the need for these skills, suggesting the possibility of using the SIBT for trainer education.

Goniometers, commonly used to measure joint range of motion, are increasingly being replaced by smartphones in the field of sports. However, the position, orientation, and fixation methods for smartphone placement and the applications used have not been validated. This study aimed to determine the validity of measured angles using a smartphone application based on its position and orientation. We measured thirty different angles by using two cardboard sheets, each containing fifteen randomly drawn lines. The cardboard pieces were placed on a horizontal desk and a vertical wall perpendicular to the floor, and a smartphone was placed in six orientations to measure each angle. A protractor was used for validation.

In the Horizontal-Vertical position (HVP), with the smartphone placed on its short side perpendicular to the desk, measurements were unclear and unusable. Fixation errors were observed on the smartphone’s Horizontal-Supine position (HSP) (p=0.01), placed parallel to the desk, and proportional errors were observed on the Horizontal-Lateral recumbent position (HLP) (p=0.034), measured with the long side placed perpendicularly to the desk. Although measurement at the HVP was unreliable, others were accurate. Future verification with new smartphones with improved and updated gyro and accelerometer sensors is needed.