Past reports have reinforced global public health concerns related to physical inactivity. Recent global efforts to increase physical activity and decrease sedentary behaviors have been underway. The development and release of Report Cards on physical activity for children and youth have in many countries improved advocacy and social mobilization with the intent of increasing young people’s activity by influencing perceptions, priorities, policies, and practices. In 2016, 38 countries including Japan produced a cross-country comparison finding that showed higher physical activity and lower sedentary behavior in countries that reported poorer infrastructure, and lower physical activity and higher sedentary behavior in countries that reported better infrastructure. This suggests that autonomy to play, travel, chore requirements and/or fewer attractive sedentary pursuits, rather than infrastructure and structured activities, may facilitate higher levels of physical activity. Future nationally representative surveys on overall physical activity, active play, and community and the built environment are needed. The establishment of evaluation methods for the international comparison of daily physical activity and its factors in Japanese children and youth are needed.

The purpose of this study was to assess an impact of water immersion recovery after short distance swimming on the recovery process in pulmonary functions in individuals with the past history of bronchial asthma (PHA). Eleven Japanese healthy males with PHA (23 years) volunteered to perform two bouts of a 25-m maximal front crawl session in an indoor pool. The two bouts were separated by either 10-min of recovery on the land (L-session) or the same condition with water immersion to the neck (W-session), using a counterbalanced crossover design. Water temperature was 30 °C. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV_1.0) (%predicted) were measured according to the following time course; at baseline (REST), water immersion to the neck (WIN) before the swimming session, after 5-min (REC-5) and 10-min (REC-10) recovery with the assessment of dyspnea sensation (ADS) at the same time point. %FVC and %FEV_1.0 at WIN, REC-5 and REC-10 in the W-session were significantly lower than those REST. A similar reduction was observed at WIN in the L-session, and %FEV_1.0 at REC-5 was significantly different from those REST. The subjects had higher ADS at REC-5 in both sessions compared with those REST. %FVC and %FEV_1.0 at REC-5 and REC-10 in W-session were significantly lower than those at REC-5 and REC-10 in L-session. These results indicates a negative impact of not only water immersion recovery but also recovery on the land after short distance swimming on pulmonary function in individuals with PHA.

Physical constitution consists of biologically different components, such as fat mass (FM) associated with various risks and fat-free mass (FFM) associated with physical fitness. Given a hypothesis that body composition to provide the best physical fitness is the healthiest, we estimated the relationship between fat-to-lean ratio (FLR= FM/FFM) and physical fitness outcomes in school children. Five hundred and three 4^th grade school children aged at 10 years were recruited and their body composition were measured by bioelectrical impedance analysis. They underwent physical fitness test including grip strength, sit-up, sit & reach, side step, 20m shuttle run, 50m dash, standing broad jump, softball throw. According to the sexes, the subjects were classified into 5 ranks (quintile) based on their heights, and subsequently stratified into 4 groups (quartile) in each height-rank (quintile) groups based on their FLR. By grouping the same FLR quartile group in 5 height-ranks (quintile groups), quartile groups (FLR-1 to FLR-4) were compared among their outcome of physical fitness test. Without relation to heights and FFM, 20m shuttle run as an index of cardiorespiratory fitness, 50m dash and standing broad jump showed significant difference among groups in stepwise manner in both boys and girls, where the most lean group had highest capacity. FM and FFM have to be discriminated each other, because of their characteristic biological significance. FLR, strongly correlated to aerobic power, is a useful index to estimate body composition associated with physical fitness.

The purpose of this study was to investigate relationship between the shoulder pain and the flexibility of the shoulder in Japanese elite male water polo players. We also conducted to find the physical characteristics of the range of shoulder rotation. Subjects were Japanese elite male water polo players that was 30 (study 1) and 40 (study 2). We measured and compared shoulder flexibility by finger vertebral distance (FVD). In study 2, a standard universal goniometer was utilized to measure range of shoulder rotation with the arm in 90 degrees of abduction. There is significant correlation range of motion on the dominant shoulder showed significant decrease in internal rotation and increase external rotation. The results indicate that decrease exists in the shoulder flexibility of elite water polo players with pain. Furthermore, our findings suggest that prevention or rehabilitation of painful water polo player’s dominant shoulder is considered to be existing two reasons that are at risk of developing shoulder pain because of the repetitive nature of swimming combined with throwing.

The purpose of the present study was to examine the associations between physical fitness and body fatness with blood lipid profile in 231 Japanese children and adolescents (12.1 ± 1.5 years). The primary outcomes of the present study were a lipid risk score which was calculated by summing up z scores of three lipid items (triglycerides, low density lipoprotein-cholesterol, and high density lipoprotein-cholesterol). Physical fitness was assessed by using the Japanese standardised fitness test. For body fatness, a percentage of overweight was calculated with using age-, sex-, height-specific standardised body mass. For combined analysis (fitness × fatness), the participants were cross-tabulated into four groups (Non-Obese/Higher-Fit, Non-Obese/Lower-Fit, Obese/Higher-Fit, and Obese/Lower-Fit). The results demonstrated that the participants in fitness categories A/B [most fit] and C [middle] demonstrated the lower (better) lipid risk score than the participants in fitness categories D/E [least fit] (F _{(2, 222)} = 6.03, p = .003). For body fatness, the lipid risk score in obese group was significantly higher (worse) than that in thin and normal groups (F _{(2, 222)} = 6.08, p = .004). The combined analysis showed that there was a significant interaction (fitness × fatness) on the lipid risk score (F _{(1, 221)} = 4.05, p = .047), suggesting that Obese/Lower-Fit group had the worst risk score compared to the other groups. The present study suggests that improving both fitness and body fatness might be important for better lipid profile in Japanese children and adolescents.

High fat diet consumption induces fat accumulation in the liver. An understanding of when liver fat accumulation begins is important for exploring the mechanisms underlying fatty liver. The aim of this study was to investigate the processes of fat accumulation in the liver during high fat diet consumption with or without exercise using computed tomography (CT). Male 6 week old C57BL/6J mice were randomly assigned to the normal diet or high fat diet group. After 6 weeks, mice in the high-fat diet group were further divided into voluntary wheel exercise (HFD+Ex) and no exercise (HFD) groups. We measured body weight, food intake and locomotor activity in all mice. Liver fat accumulation was measured by CT scan weekly. Blood and tissue sampling was performed at the end of the experimental period. Following the 6 week exercise period, total body, mesenteric fat and liver weight in the HFD+Ex group were significantly lower than those in the HFD group. Alanine aminotransferase levels improved in HFD+Ex mice compared with those of HFD mice. The hounsfield unit value in HFD mice decreased between 3 and 8 weeks, suggesting that liver fat accumulation accelerated during this period. In contrast this decrease was not observed one week after exercise in HFD+Ex mice. These results suggest that liver fat accumulation estimated by CT was not observed until the 3rd week of high fat feeding while the effects of voluntary wheel exercise appeared immediately.

We developed a periodic hypobaric hypoxic environment (PHHE) system. Characteristics of this system varied between decreased pressure at an altitude of 1,500 m for 180 seconds and increased pressure at an altitude of 0 m for 180 seconds. The present study aimed to determine the effects of PHHE on physiological responses during endurance exercise and recovery after exercise. This study included 12 healthy men, and they provided written informed consent. All subjects performed a cycling exercise for 30 minutes and recovered after exercise for 10 minutes. The exercise protocol was performed with 20% maximum oxygen uptake for 6 minutes (warm-up), 40 % for 18 minutes (main exercise), and 20 % for 6 minutes (cool down). We established two experimental conditions: exercise with the PHHE and the control (C). The C condition involved exercise using the PHHE at an altitude of 0 m, and the atmospheric pressure was not changed. In the PHHE condition, the atmospheric pressure was changed periodically from 967 to 817 hPa (the external pressure was 1,008 hPa). Subjects’ heart rate (HR), blood pressure (BP), arterial oxygen saturation (SpO₂), rating of perceived exertion, and respiratory responses were measured in both conditions. The SpO₂, HR and systolic BP during exercise were significantly lower in the PHHE condition than in the C condition. The HR post-exercise was significantly lower. After exercise, the ln HF, an index of cardiac parasympathetic nervous system modulation, was significantly higher. In conclusion, during endurance exercise, cardiocirculatory responses in the PHHE condition were decreased.

The purpose of this study was to clarify the effects of external and internal factors (EF and IF, respectively) on attention during exercise on a cross test in elderly inpatients with respect to physical and attention functions. The subjects were 27 elderly inpatients with orthopedic diseases, cerebrovascular diseases, or disuse syndrome (mean age, 77.8±8.8 years). They were randomly divided into two groups, and instructed to pay attention in different directions for a cross test. Measurement was conducted in a pretest, during a 14-day period of practice, during a 7-day period of discontinuation, and in a post-test. In the EF group, the subjects were instructed to place their body weight on the floor while paying attention to the floor. In the IF group, they were instructed to tilt their whole body while paying attention to the body. The physical function was evaluated using the Berg Balance Scale and Timed Up and Go Test, attention using the Trail Making Test Part-A. In the EF and IF groups, the physical and attention functions were lower than the reference ranges, and a cross test showed a significant improvement in the EF group both 7 days and post-test. On the other hand, there were no correlations between the improvement rating for the cross test in pre- and post-tests in the EF and IF groups and physical and attention functions. These results suggest that the use of EF improves the cross test in patients with mild physical, attention hypofunction, promoting exercise learning.