The global outbreak of novel coronavirus infection in the winter of 2020 led to city lockdowns and curfews in many parts of the world, forcing university athletes to suspend training. De-training negatively affects athletic performance. In school sports, temporary closures due to infectious diseases often occur yearly. Therefore, this study aimed to clarify the differences in the changes in various physical fitness factors between two different residential environments during the suspension of team activities. The observation period was 7 months, from March to September 2020. The baseline period was defined as the period before the voluntary suspension of team activities (March), the de-training period was the timeframe of suspension of team activities (April-May), and the follow-up period was defined as the period after the resumption of team practice (June-September). The study participants included 17 dormitory students and 14 home-schooled students in a university rugby team. The dormitories were equipped with training equipment and space for minimal training. The team staff provided a training program for both dormitory and non-dormitory students, which could be followed at home during periods when team practices were suspended. This study showed sig-nificant differences between dormitory and home-schooled students in the maximum lifting weight measurement of narrow chinning at baseline and after de-training. Other physical fitness factors did not differ significantly between groups or measurement periods. Although this study sample size was small and sufficient power could not be obtained, home weight training could maintain a certain level of maximum muscle strength as in the present study, suggesting that preparation for back exercises that can be performed at home is essential for the back muscles.

The Japanese Society of Clinical Sports Medicine and the Japanese Society for Athletic Training have developed the consensus recommendations on injury and illness surveillance methodology. This study aimed to assess the internal completeness and validity of data collected using the recommended methods by the academic societies. Participants were recruited using two methods : snowball sampling and outreach via social media platforms. Individuals who were involved in the evaluation of athletes and reporting of sports injuries on a daily basis were enrolled. They were tasked to read seven fictitious injury reports and fill out relevant information on a standardized injury and illness form. The internal completeness and inter-rater reliability were examined for the following variables : date of onset of injury/illness, activity type, history of injury, mechanism of injury, mode of onset, body part, pathology type, side of injury, date of full return to play, illness evaluation, and illness diagnosis. The inter-rater reliability was evaluated using Flaissʼ kappa coefficients. A total of 70 and 367 responses were analyzed from snowball sampling and social media, respectively. The internal completeness of the data was almost perfect when reported by licensed/certified healthcare professionals (97.8-99.4%) except for dentists (73.68%). Regarding internal validity, the data collected for Illness evaluation and illness diagnosis had poor agreements (k=−0.11-0). In conclusion, the standardized reporting form consisted of recommended variables was suitable in collecting comprehensive data with a high internal completeness. However, the inter-rater reliability of the data collected for illness evaluation and illness diagnosis was notably low, indicating a need for improved methodologies．

In this study, we examined the relationship between changes in physical fitness and swimming performance in each case where the performance improved and stopped during the maturation period. The measurement items were body composition, morphology, and physical fitness, including medicine ball throwing, sit-up, and vertical jump, which were measured from the sixth-grade elementary school to the second-grade junior high school. In the case of improved swimming performance, physical fitness was improved, but in the case of stagnation, physical fitness decreased significantly. In the training plan for adolescent female swimmers, not only swimming practice but also improvement of physical training may be required.

This study analyzed the effects of sensory stimulation to the head using a headband on body orientation ability, joint movement, and physical activity in healthy adults. The results showed a significant increase in the scores assessing body orientation ability with the use of the headband. Additionally, the range of motion for head rotation and the finger-floor distance significantly increased while wearing the headband. Moreover, a specially designed headband with areas of varying pressure in the front, back, and sides demonstrated a stronger tendency to improve head rotation and forward bending compared to a commercially available headband. It was inferred that the headband enhanced sensory input from the head, thereby improving body orientation ability and subsequently enhancing movement.