Delayed Eating Schedule Raises Mean Glucose Levels in Young Adult Males: a Randomized Controlled Cross-Over Trial.

BACKGROUND: Misalignment of meals to the biological clock may cause adverse effects on glucose metabolism. However, the effects of repeated different eating schedules (early compared with late) on glucose concentration throughout the day are poorly understood. OBJECTIVES: We examined the effects of different eating schedules on the 24-h glucose response using a continuous glucose monitor (CGM). METHODS: Eight young adult males (age, 20.9 ± 3.4 y; body mass index: 21.3 ± 1.8 kg/m2) each followed 2 different eating schedules (early [08:30, 13:30, and 19:30] and late [12:00, 17:00, and 23:00]) in random order. These diet interventions were conducted for 8 d, with an experimental period of 3 d and 2 nights (from dinner on day 7) after 7 d of free living. The 3 meals in each intervention were nutritionally equivalent (55% carbohydrate, 15% protein, and 30% fat). The 24-h mean interstitial glucose concentration on day 8 was obtained under controlled conditions using the CGM (primary outcome). These concentrations were compared among the following 3 schedules using Dunnett's test, with the early eating schedule as reference (1 compared with 2 and 1 compared with 3): 1) early eating schedule (control), 2) late eating schedule according to the clock time (08:00 on day 8 to 08:00 on day 9), and 3) late eating schedule according to the time elapsed since the first meal for 24 h. RESULTS: The 24-h mean ± SD interstitial glucose concentrations when participants followed the late eating schedule were higher than those when they followed the early eating schedule in terms of clock time (91.2 ± 2.9 compared with 99.2 ± 4.6 mg/dL, P = 0.003) and time elapsed (91.2 ± 2.9 compared with 98.3 ± 3.8 mg/dL, P < 0.001). CONCLUSIONS: A late eating schedule increases the mean 24-h interstitial glucose concentration in young adult males. This insight will have useful implications in determining meal timings, especially for those with conditions such as diabetes.

Prediction of the Physical Activity Level of Community-Dwelling Older Japanese Adults with a Triaxial Accelerometer Containing a Classification Algorithm for Ambulatory and Non-Ambulatory Activities.

Accurate methods for the prediction of the total energy expenditure and physical activity level (PAL) in community-dwelling older adults have not been established. Therefore, we examined the validity of estimating the PAL using an activity monitor (Active style Pro HJA-350IT, [ASP]) and proposed correction formulae for such populations in Japan. Data for 69 Japanese community-dwelling adults aged 65 to 85 years were used. The total energy expenditure in free-living conditions was measured with the doubly labeled water method and the measured basal metabolic rate. The PAL was also estimated from metabolic equivalent (MET) values obtained with the activity monitor. Adjusted MET values were also calculated with the regression equation of Nagayoshi et al. (2019). The observed PAL was underestimated, but significantly correlated, with the PAL from the ASP. When adjusted using the Nagayoshi et al. regression equation, the PAL was overestimated. Therefore, we developed regression equations to estimate the actual PAL (Y) from the PAL obtained with the ASP for young adults (X) as follows: women: Y = 0.949 × X + 0.205, mean ± standard deviation of the prediction error = 0.00 ± 0.20; men: Y = 0.899 × X + 0.371, mean ± standard deviation of the prediction error = 0.00 ± 0.17.

Neighborhood-level socioeconomic factors moderate the association between physical activity and relative age effect: a cross-sectional survey study with Japanese adolescents.

BACKGROUND: Relative age effect is defined as a phenomenon where children born early generally perform better than children born later in the same cohort. Physical activity is an important factor that might be influenced by the relative age effect. Socioeconomic factors (e.g., parent's income, education level) are also associated with the adolescent's physical activity. However, no existing study has examined whether socioeconomic factors moderate the relative age effect on the adolescent's physical activity. This study aims to clarify whether and how birth month and socioeconomic factors relate to organized sports and physical activity among adolescents in Japan. METHODS: We conducted a questionnaire survey targeting 21,491 adolescents who live in a widespread neighborhood. We included 8102 adolescents (4087 males and 4015 females: mean age 13.1 ± 1.4) in the analysis. Based on the participants' birth months, we divided them into four groups (April to June, July to September, October to December, January to March). We asked participants to report their organized sports participation. Using the International Physical Activity Questionnaire for Japanese Early Adolescents, we identified their moderate to vigorous physical activity (MVPA). Neighborhood-level socioeconomic factors (areal deprivation, average annual income, education level) were analyzed based on national surveys, such as the population census. We performed multilevel logistic and linear regression analysis for organized sports participation and MVPA, respectively. Moreover, a simple slope analysis was implemented if the interaction between birth month and socioeconomic factor was significant in the multilevel linear regression analysis. RESULTS: Among males, relatively younger adolescents (adolescents who were born later in the same grade) were less likely to participate in organized sports activites (OR=0.90, 95% CI 0.82-0.97, p<0.05), while both males and females engaged in less MVPA (b=-0.54, b=-0.25, p< 0.01, respectively). We observed an interaction between birth month and socioeconomic factors. Among males in low-income neighborhoods, and females in more deprived neighborhoods, relatively younger adolescents engaged in less MVPA. CONCLUSIONS: Socioeconomic factors moderate the relative age effect on adolescents' physical activity. The relative age effect on adolescents' physical activity might be more likely to appear among adolescents from socioeconomically disadvantaged neighborhoods.

Association Between Age of Achieving Gross Motor Development Milestones During Infancy and Body Fat Percentage at 6 to 7 Years of Age.

OBJECTIVES: The later achievement of gross motor milestones during infancy is associated with adiposity in early childhood. However, the associations between gross motor development and adiposity after entering primary school are unclear. This study examined the associations between the ages at which six gross motor milestones were achieved and adiposity during early school years. METHODS: This retrospective study was conducted in 2012 and 2013. Data were collected from 225 first-grade primary school children (mean age, 6.9 years; 39% girls). Adiposity was assessed using dual-energy X-ray absorptiometry and expressed as body fat percentage. Data describing the ages of achieving six gross motor milestones (holding head up, sitting, crawling, standing supported, walking supported, and independent walking) were obtained from the Maternal and Child Health Handbooks. RESULTS: Mean body fat percentage was 21.7%. Multiple linear regression analyses revealed that later ages of achieving crawling (p < .001 [95% confidence interval: 0.33-1.16]), standing supported (p < .001 [95% confidence interval: 0.64-1.65]), and walking supported [p = .013 (95% confidence interval: 0.13-1.07)] were associated with increased fat. However, the ages of achieving holding head up (p = .053), sitting (p = .175), and independent walking (p = .736) were not statistically significant. CONCLUSIONS: Achieving crawling, standing supported, and walking supported later predict increased body fat when aged 6-7 years. The practice of observing gross motor milestone achievements may allow early targeted interventions to optimize body composition before beginning school and thereby, potentially prevent childhood obesity.

Does earlier acquisition of motor competence promote pubertal physical activity in Japanese elementary school children: A 4-year follow-up study.

This 4-year follow-up study investigated which profile of motor competence (MC) in early childhood more strongly correlated with moderate-to-vigorous physical activity (MVPA) in early pubescence. A total of 247 first-grade children (152 boys) aged 6 to 7 years old participated in the baseline measurement. MVPA was measured using an accelerometer annually until the fifth grade. Body fat percentage was assessed using dual-energy X-ray absorptiometry at baseline. MC included fundamental movement skills (FMS) and motor performance, which were assessed in terms of locomotor and object control. FMS was assessed by the Test of Gross Motor Development-2, while motor performance (locomotor: run, hop, jump, and side-step, object control: throw, kick, and hand dribble) was assessed by Japanese Physical Fitness and Motor Abilities Test at baseline. Multiple regression analysis showed that locomotor and object control performance were significant predictors of MVPA in later grades in boys but not in girls. These associations between locomotor performance and MVPA mainly remained significant after controlling for body fat and MVPA at baseline. FMS in both genders was not a significant predictor of MVPA in early pubescence. This study suggests that appropriate strategies for increasing MVPA from prepubescence to early pubescence may differ between boys and girls.

Results from the Japan 2022 report card on physical activity for children and youth.

Background/Objective: The 2020 Tokyo Olympics and Paralympic was held in 2021, although postponed due to the spread of COVID-19. This event might have an impact on physical activity (PA) of children and adolescents, but the national data on PA during the pandemic were not available. Therefore, the goal of the 2022 Japan Report Card on Physical Activity for Children and Youth (The 2022 Japan Report Card) is to assess and track levels of health behaviors related to PA, and health outcomes in Japanese children and adolescents, and environments and government strategy for PA just before the pandemic. Methods: The 2022 Japan Report Card consists of health behaviors and outcomes (8 indicators), and influences on health behaviors (4 indicators). Nationally representative data were used to score the indicators. Results: The key five health behaviors and outcomes (Overall PA: B-; Organized Sport: B-; Active Transportation: A-; Physical fitness: B, Weight status: A) were favorable. Sedentary Behavior and Sleep received C- and D- grades, respectively. Active Play could not be graded (INC). In the influences domain, Family and Peers was graded as C-, while School (B+), Community and Environment (B), and Government (B) were favorable. Conclusions: The 2022 Japan Report Card shows that Japanese children and adolescents had favorable levels of overall PA, active transportation to and from school, and weight status, and there was a generally favorable environment for PA and health, though sedentary behavior and sleep were unfavorable. Future nationally representative surveys on active play are needed.

The product of trunk muscle area and density on the CT image is a good indicator of energy expenditure in patients with or at risk for COPD.

BACKGROUND: Physical inactivity due to cachexia and muscle wasting is well recognized as a sign of poor prognosis in chronic obstructive pulmonary disease (COPD). However, there have been no reports on the relationship between trunk muscle measurements and energy expenditure parameters, such as the total energy expenditure (TEE) and physical activity level (PAL), in COPD. In this study, we investigated the associations of computed tomography (CT)-derived muscle area and density measurements with clinical parameters, including TEE and PAL, in patients with or at risk for COPD, and examined whether these muscle measurements serve as an indicator of TEE and PAL. METHODS: The study population consisted of 36 male patients with (n = 28, stage 1-4) and at risk for (n = 8) COPD aged over 50 years. TEE was measured by the doubly labeled water method, and PAL was calculated as the TEE/basal metabolic rate estimated by the indirect method. The cross-sectional areas and densities of the pectoralis muscles, rectus abdominis muscles, and erector spinae muscles were measured. We evaluated the relationship between these muscle measurements and clinical outcomes, including body composition, lung function, muscle strength, TEE, and PAL. RESULTS: All the muscle areas were significantly associated with TEE, severity of emphysema, and body composition indices such as body mass index, fat-free mass, and trunk muscle mass. All trunk muscle densities were correlated with PAL. The product of the rectus abdominis muscle area and density showed the highest association with TEE (r = 0.732) and PAL (r = 0.578). Several trunk muscle measurements showed significant correlations with maximal inspiratory and expiratory pressures, indicating their roles in respiration. CONCLUSIONS: CT-derived measurements for trunk muscles are helpful in evaluating physical status and function in patients with or at risk for COPD. Particularly, trunk muscle evaluation may be a useful marker reflecting TEE and PAL.

Adherence to the Japanese Physical Activity Guideline During Early Childhood Among Rural Preschoolers: A Cross-sectional Study.

BACKGROUND: Physical activity (PA) guidelines for early childhood have been established worldwide, and adherence to PA guidelines has been utilized to assess the effectiveness of policies regarding PA promotion. Although there is a Japanese PA guideline for preschoolers, little is known about adherence to this recommendation. This study examined and compared proportions of meeting the Japanese PA guideline among preschoolers. METHODS: Participants comprised 821 children aged 3-6 years from all 21 preschools and childcare facilities (hereafter collectively "preschools") within Unnan City, Shimane Prefecture, Japan. Data on PA levels were collected through a parent-report questionnaire in accordance with the Japanese PA guideline. This guideline recommends that preschoolers perform PA for at least 60 minutes every day. Analyses included descriptive statistics, chi-squared, and Mann-Whitney's tests to compare adherence to the PA guideline. RESULTS: Data of 441 participants from 20 preschools were analyzed. Of these, 292 (66.2%) preschoolers met the PA guideline. Boys (70.2%) showed a significantly higher proportion of meeting the PA guideline than girls (61.2%; P = 0.048). Proportions of meeting the PA guideline among preschool grades were not statistically different. Prevalence rates of meeting the PA guideline among 20 preschools considerably varied from 14.3% to 100% (P = 0.007). CONCLUSIONS: Two-thirds of preschoolers met the Japanese PA guideline, while adherence to PA recommendations differed between genders. Moreover, there were distinct variations of adherence to PA guideline among preschools. Possible determinants that cause the differences in adherence to the PA guideline at the individual and preschool-levels should be further evaluated.

Compliance with a physical activity guideline among junior high school students.

BACKGROUND: There were no nationwide moderate- to vigorous-intensity physical activity (MVPA) data relating to Japanese adolescents. This study assessed compliance with an MVPA guideline by adolescents, using a random sampling survey in Japan. The factors associated with compliance with the guideline were also examined. METHODS: Participants were first- to third-grade Japanese junior high school students (307 boys and 255 girls). We analyzed data from the National Sports-Life Survey of Teens 2019, which used the Japanese version of physical activity (PA) questions in the World Health Organization Health Behavior in School-aged Children survey and potential correlates of MVPA. RESULTS: Compliance with the PA guideline by the World Health Organization for Japanese students was 19.0% (95% confidence interval (CI), 15.8-22.3). The compliance of boys was significantly higher than that of girls (23.1%; 95% CI, 18.4-27.8; vs 14.1%; 95% CI, 9.8-18.4). The odds of meeting the PA guideline were significantly higher for boys in the second grade than boys in the first grade (odds ratio (OR) 1.78; 95% CI, 1.02-3.09), liking PA (for all: OR: 2.97; 95% CI, 1.32-6.69; for girls: OR: 2.99; 95% CI, 1.01-8.81), and sports participation (for all: OR: 4.77; 95% CI, 2.32-9.80; for boys: OR: 6.00; 95% CI, 1.81-19.89; for girls: OR: 4.08; 95% CI, 1.63-10.21). CONCLUSIONS: The results suggest that more than 80% of junior high school students were insufficiently physically active in Japan. Preferences for PA and sports participation may be important correlates of sufficient PA.

Validity of the Use of a Triaxial Accelerometer and a Physical Activity Questionnaire for Estimating Total Energy Expenditure and Physical Activity Level among Elderly Patients with Type 2 Diabetes Mellitus: CLEVER-DM Study.

INTRODUCTION: Evaluation of total energy expenditure (TEE) and physical activity level (PAL) is important for treatment of patients with type 2 diabetes mellitus (T2DM). However, the validity of accelerometers (ACC) and physical activity questionnaires (PAQ) for estimating TEE and PAL remains unknown in elderly populations with T2DM. We evaluated the accuracy of TEE and PAL results estimated by an ACC (TEEACC and PALACC) and a PAQ (TEEPAQ and PALPAQ) in elderly patients with T2DM. METHODS: Fifty-one elderly patients with T2DM (aged 61-79 years) participated in this study. TEEACC was calculated with PALACC using a triaxial ACC (Active style Pro HJA-750c) over 2 weeks and predicted basal metabolic rate (BMR) by Ganpule's equation. TEEPAQ was estimated using predicted BMR and the PALPAQ from the -Japan Public Health Center Study-Long questionnaire. We compared the results to TEEDLW measured with the doubly labeled water (DLW) method and PALDLW calculated with BMR using indirect calorimetry. RESULTS: TEEDLW was 2,165 ± 365 kcal/day, and TEEACC was 2,014 ± 339 kcal/day; TEEACC was strongly correlated with TEEDLW (r = 0.87, p < 0.01) but significantly underestimated (-150 ± 183 kcal/day, p < 0.05). There was no significant difference in TEEPAQ and TEEDLW (-49 ± 284 kcal/day), while the range of difference seemed to be larger than TEEACC. PALDLW, PALACC, and PALPAQ were calculated to be 1.71 ± 0.17, 1.69 ± 0.16, and 1.78 ± 0.24, respectively. -PALACC was strongly correlated with PALDLW (r = 0.71, p < 0.01), and there was no significant difference between the 2 values. PALPAQ was moderately correlated with PALDLW (r = 0.43, p < 0.01) but significantly overestimated. Predicted BMR was significantly lower than the BMR -measured by indirect calorimetry (1,193 ± 186 vs. 1,262 ± 155 kcal/day, p < 0.01). CONCLUSIONS: The present ACC and questionnaire showed acceptable correlation of TEE and PAL compared with DLW method in elderly patients with T2DM. Systematic errors in estimating TEE may be improved by the better equation for predicting BMR.

Association between 24-hour movement guidelines and physical fitness in children.

BACKGROUND: Physical fitness levels in Japanese children are lower than those in the 1980s. Twenty-four hour movement guidelines were recently developed to improve both present and future health of children. This study examined whether meeting the 24 h movement guidelines was associated with physical fitness measures in primary school children. METHODS: Participants were 243 Japanese children (9.4 ± 1.7 years). Moderate-to-vigorous physical activity (MVPA) was evaluated using accelerometry. Sleep duration and screen time were reported. Physical fitness was assessed by grip strength, sit-ups, sitting trunk flexion, and 20 m shuttle run test. Meeting the 24 h movement guidelines was defined as: 9-11 h / night of sleep, ≤2 h/day of screen time, and at least 60 min/day of MVPA. The associations between physical fitness and the recommendations were analyzed using analysis of covariance. RESULTS: Children meeting the MVPA recommendation alone performed better on the 20 m shuttle run and sit-up test compared to those not meeting the recommendation (number of laps: 41 vs 36, P = 0.009 and number of repetitions: 16.3 vs 14.7, P = 0.021). Children meeting the combination of MVPA and sleep recommendation scored significantly higher on the sit-up test compared to those not meeting the recommendations (number of repetitions: 16.5 vs 15.0, P = 0.038) but the effect was similar to that of the MVPA reference only. Meeting all three 24 h movement guidelines was not associated with measures of fitness in this sample. Meeting the MVPA recommendation was associated with greater aerobic fitness and muscle endurance. CONCLUSIONS: In order to enhance children's physical fitness, public health recommendations should primarily target MVPA.

The Relationship between Changes in Organ-Tissue Mass and Sleeping Energy Expenditure Following Weight Change in College Sumo Wrestlers.

Background and objectives: It has been well established that the resting energy expenditure (REE) for the whole body is the sum of the REE for each organ-tissue in young and middle-aged healthy adults. Based on these previous studies, although it is speculated that sleeping energy expenditure (SEE, which has small inter-individual variability) changes with a commensurate gain or reduction in the resting metabolic rate of each organ-tissue, it is unclear whether a change in organ-tissue masses is directly attributed to the fluctuation of SEE at present. This study aimed to assess the relationship between changes in organ-tissue mass and sleeping energy expenditure (SEE) following weight change in college Sumo wrestlers. This included blood analysis, which is related to energy expenditure. Materials and Methods: A total of 16 healthy male college Sumo wrestlers were recruited in this study. All measurements were obtained before and after weight change. Magnetic resonance imaging measurements were used to determine the volume of the skeletal muscle (SM), liver, and kidneys, and an indirect human calorimeter was used to determine SEE before and after weight change. Results: The change in body mass and SEE ranged between -8.7~9.5 kg, and -602~388 kcal/day. Moreover, changes in SM, liver, and kidneys ranged between -3.3~3.6 kg, -0.90~0.77 kg, and -0.12~0.07 kg. The change in SEE was not significantly correlated with the change in SM or liver mass, nor with blood analyses; however, a significant relationship between the change in kidney mass and SEE was observed. Conclusions: Based on our results, there is a possibility that the mass of the kidneys has an effect on the change in SEE following weight change in college Sumo wrestlers.

Gender differences in physical activity and sedentary behavior of Japanese primary school children during school cleaning time, morning recess and lunch recess.

BACKGROUND: The school environment provides crucial opportunities for children to engage in health-promoting physical activity (PA). Japanese children clean their schools and have recess time every school day. The primary aim of the study is to describe the levels of physical activity during school cleaning and recess time while comparing it between genders. METHODS: PA and sedentary behavior (SB) of 230 boys and 252 girls aged 6-12 years-old from 14 public primary schools were assessed for 7 consecutive days with a triaxial accelerometer. Minutes of SB, and moderate-to-vigorous PA (MVPA) as a percentage in each of school cleaning time (15 min/day: 58% of the 14 schools or 20 min/day), morning recess time (15 min/day: 6% or 20 min/day) or lunch recess time (15 min/day: 29%, 20 min/day: 47% or 25 min/day) were evaluated. A one-way analysis of variance or Student's t test was used to examine differences in %PAs and %SB between school cleaning time and morning and lunch recess time, and between genders. RESULTS: In a school day, the percentage of total daily MVPA during school cleaning time, morning recess and lunch recess time was 19.4 ± 6.8% (15.2 ± 5.3 min/day) for boys and 16.9 ± 5.8% (10.5 ± 4.3 min/day) for girls. For boys, the proportions of MVPA in morning and lunch recesses and SB during the morning recess were significantly higher than during school cleaning time (p < 0.001). For girls, similar results were obtained and the SB during lunch recess was also higher than during school cleaning time (p < 0.001). CONCLUSIONS: These findings suggest that the total amount of school cleaning time, recess and lunch time likely contribute to daily MVPA but the beneficial effects should be further explored in future intervention studies.

Status of physical activity in Japanese adults and children.

Objective: To summarise the status of physical activity in Japanese adults and children. Methods: Results obtained by several nationwide surveys such as the National Health and Nutrition Survey of Japan carried out annually were reviewed. Moreover, relevant guidelines or summaries and results of papers were introduced. Results: Average step counts have decreased by about 1000 steps from peak values observed before the year 2000, but the decrease after 2010 was less than 200 steps in both sexes. Based on the results of a meta-analysis and national survey, a new physical activity guideline for Japanese, 'ActiveGuide', was published. The most important message is the '+10', which indicates an 'additional 10 minutes of moderate-to-vigorous PA per day to the status quo'. According to the Japan Report Card on Physical Activity for Children and Youth, there was no nationwide survey on the overall Physical Activity Levels for children. However, grades for Organised Sports Participation and Active Transportation were very good. The mean values of cardiorespiratory endurance for Japanese children were around the 90th centiles of the international criterion-referenced data. Conclusions: More accurate measures of daily physical activity, sedentary behaviour and sleep should be developed for a nationwide survey.

Validity of Combination Use of Activity Record and Accelerometry to Measure Free-Living Total Energy Expenditure in Female Endurance Runners.

Yoshida, A, Ishikawa-Takata, K, Tanaka, S, Suzuki, N, Nakae, S, Murata, H, Taguchi, M, and Higuchi, M. Validity of combination use of activity record and accelerometry to measure free-living total energy expenditure in female endurance runners. J Strength Cond Res 33(11): 2962-2970, 2019-Herein, we attempted to prove the validity of a new approach to assessing total energy expenditure (TEE) that combines activity recording and accelerometry in athletes. Eight female endurance runners participated in this study. We measured TEE over 8 days in the regular training season by using the doubly labeled water (DLW) method. In the combined method, an activity record of the rating of perceived exertion (RPE) was used to estimate energy expenditure (EE) during the training period, whereas a triaxial accelerometer was used to evaluate EE during the nontraining time over the TEE measurement period using the DLW method. Training EE was calculated from the subjects' individual rating of perceived exertion-EE correlations provided by the exercise tolerance test. Resting metabolic rate (RMR) was measured using indirect calorimetry. There were no significant differences in TEE, activity-induced EE (AEE), or physical activity level (PAL; TEE/RMR) between the DLW method and the combined method (TEE, 3,032 ± 344 vs. 3,033 ± 495 kcal·d; AEE, 1,585 ± 303 vs. 1,586 ± 442 kcal·d; and PAL, 2.68 ± 0.37 vs. 2.68 ± 0.48, respectively). Significant positive correlations and no systematic errors were observed in AEE and PAL. Intraclass correlation coefficients were high (TEE, 0.785; AEE, 0.841; and PAL, 0.779, respectively). These findings suggest that the combined method has high validity against the DLW method. Thus, the combined method would be able to estimate free-living TEE in the regular training season for female endurance runners.

Results from the Japan's 2018 report card on physical activity for children and youth.

BACKGROUND: The momentum to promote physical activity (PA) by various government agencies such as the Japan Sports Agency established in 2015, academic organizations, and companies is increasing towards the Tokyo Olympic and Paralympic Games. The goal of the 2018 Japan Report Card on Physical Activity for Children and Youth is to assess and track levels of health behaviors related to PA in Japanese children and youth, facilitators and barriers for PA, and related health outcomes. METHODS: Nationally representative data were used to score the indicators. RESULTS: The 2018 Japan Report Card on Physical Activity for Children and Youth consists of health behaviors and outcomes (7 indicators), and influences on health behaviors (4 indicators). The key four health behaviors and outcomes (Organized Sport Participation: B-; Active Transportation: A-; Physical fitness: A, Weight status: A) were favorable. Sedentary Behavior received C- grade, while 2 indicators (Overall Physical Activity, and Active Play) could not be graded. In the Influences domain, Family Influence and Community were graded as C-, while School (B+), Community and Environment (B-), and Government Strategies and Investments (B) were favorable. CONCLUSIONS: The 2018 Japan Report Card on Physical Activity for Children and Youth shows that Japanese children and youth have favorable levels of organized sport participation, active transportation to and from school, and physical fitness and weight status. Future nationally representative surveys on overall PA and active play are needed.

Estimating metabolic equivalents for activities in daily life using acceleration and heart rate in wearable devices.

BACKGROUND: Herein, an algorithm that can be used in wearable health monitoring devices to estimate metabolic equivalents (METs) based on physical activity intensity data, particularly for certain activities in daily life that make MET estimation difficult. RESULTS: Energy expenditure data were obtained from 42 volunteers using indirect calorimetry, triaxial accelerations and heart rates. The proposed algorithm used the percentage of heart rate reserve (%HRR) and the acceleration signal from the wearable device to divide the data into a middle-intensity group and a high-intensity group (HIG). The two groups were defined in terms of estimated METs. Evaluation results revealed that the classification accuracy for both groups was higher than 91%. To further facilitate MET estimation, five multiple-regression models using different features were evaluated via leave-one-out cross-validation. Using this approach, all models showed significant improvements in mean absolute percentage error (MAPE) of METs in the HIG, which included stair ascent, and the maximum reduction in MAPE for HIG was 24% compared to the previous model (HJA-750), which demonstrated a 70.7% improvement ratio. The most suitable model for our purpose that utilized heart rate and filtered synthetic acceleration was selected and its estimation error trend was confirmed. CONCLUSION: For HIG, the MAPE recalculated by the most suitable model was 10.5%. The improvement ratio was 71.6% as compared to the previous model (HJA-750C). This result was almost identical to that obtained from leave-one-out cross-validation. This proposed algorithm revealed an improvement in estimation accuracy for activities in daily life; in particular, the results included estimated values associated with stair ascent, which has been a difficult activity to evaluate so far.

Simultaneous Validation of Seven Physical Activity Questionnaires Used in Japanese Cohorts for Estimating Energy Expenditure: A Doubly Labeled Water Study.

BACKGROUND: Physical activity questionnaires (PAQs) used in large-scale Japanese cohorts have rarely been simultaneously validated against the gold standard doubly labeled water (DLW) method. This study examined the validity of seven PAQs used in Japan for estimating energy expenditure against the DLW method. METHODS: Twenty healthy Japanese adults (9 men; mean age, 32.4 [standard deviation {SD}, 9.4] years, mainly researchers and students) participated in this study. Fifteen-day daily total energy expenditure (TEE) and basal metabolic rate (BMR) were measured using the DLW method and a metabolic chamber, respectively. Activity energy expenditure (AEE) was calculated as TEE - BMR - 0.1 × TEE. Seven PAQs were self-administered to estimate TEE and AEE. RESULTS: The mean measured values of TEE and AEE were 2,294 (SD, 318) kcal/day and 721 (SD, 161) kcal/day, respectively. All of the PAQs indicated moderate-to-strong correlations with the DLW method in TEE (rho = 0.57-0.84). Two PAQs (Japan Public Health Center Study [JPHC]-PAQ Short and JPHC-PAQ Long) showed significant equivalence in TEE and moderate intra-class correlation coefficients (ICC). None of the PAQs showed significantly equivalent AEE estimates, with differences ranging from -547 to 77 kcal/day. Correlations and ICCs in AEE were mostly weak or fair (rho = 0.02-0.54, and ICC = 0.00-0.44). Only JPHC-PAQ Short provided significant and fair agreement with the DLW method. CONCLUSIONS: TEE estimated by the PAQs showed moderate or strong correlations with the results of DLW. Two PAQs showed equivalent TEE and moderate agreement. None of the PAQs showed equivalent AEE estimation to the gold standard, with weak-to-fair correlations and agreements. Further studies with larger sample sizes are needed to confirm these findings.

Objectively evaluated physical activity and sedentary time in primary school children by gender, grade and types of physical education lessons.

BACKGROUND: During the typical school day, physical education (PE) gives children an opportunity for physical activity (PA) and reduces their sedentary time, but little is known about objectively evaluated PA and sedentary time during PE lessons and the differences across genders and grades. There is also a lack of research comparing PA and sedentary time among the different types of PE lessons. The primary aim of this study was to examine primary school students' moderate-to-vigorous PA (MVPA) levels and sedentary time during PE and whether there are gender or grade differences in a cross-sectional study. The secondary aim was to determine which types of PE lessons are best for increasing PA and reducing sedentary time. METHODS: Objectively evaluated MVPA and sedentary time during PE lessons in Japan with a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare) in girls (n = 221) and boys (n = 181). Minutes of sedentary time were categorized into metabolic equivalents (METs): categories ranged from sedentary time (METs ≤1.5) to MVPA (METs ≥3.0). Time tables and PE lesson types were evaluated using logs maintained by the class teachers. RESULTS: Time spent in MVPA and sedentary time were 27.3 and 24.3%, respectively. After adjustments for grade, relative body weight and school, boys spent significantly more time in MVPA compared with girls, but with an estimated mean difference of approximately 1 min. After adjustment for gender, relative body weight and school, the younger grades (1st and 2nd) spent significantly more time in MVPA and significantly less time in sedentary time compared with other grades. Moreover, after adjustments for gender, grade, relative body weight and school, the time spent in MVPA during gymnastic and track and field lessons was significantly lower than that during ball game lessons. Sedentary time during gymnastic lessons was significantly longer than in track and field and ball game lessons. CONCLUSIONS: Children did not engage in much MVPA and also spent time in sedentary time during PE, but there are no gender differences. The children were most active during ball game lessons. Therefore, it is important to increase MVPA and reduce sedentary time during PE in both genders.

Lower youth steps/day values observed at both high and low population density areas: a cross-sectional study in metropolitan Tokyo.

BACKGROUND: Physical activity among children and adolescents (collectively, youth) is important to ensure adult health. Population density is a factor that affects physical activity via various environmental factors. However, the relationship between population density and physical activity among youth is not fully understood, especially in extremely high density area. The aim of this study was to examine the relationship between population density and physical activity of youth using pedometer-determined step data. METHODS: A total of 13,688 youth between 6 to 15 years of age were identified from the 2011 Tokyo Metropolitan Survey of Physical Fitness, Physical Activity and Lifestyle. Participants were divided into five subgroups according to the population density of their municipality of residence. The population density's fixed effects on in-school, out-of-school, and daily total step count adjusted for gender and school grade were estimated. RESULTS: The lowest (< 2500 people/km2) and highest (> 10,000 people/km2) population density subgroups had significantly lower daily total step count and out-of-school step count than those of the reference population (5000-7500 people/km2). In contrast, in-school step count did not significantly differ according to population density. CONCLUSIONS: Both low population density and also high population density were related to lower step count. Low physical activity in high density areas has not been well documented in previous research. Considering population growth in urbanized area globally, these results suggest the importance of continued research of physical activity determinants in high population density areas.