Relationship between adherence to WHO “24-Hour Movement Guidelines for the Early Years” and motor skills or cognitive function in preschool children: SUNRISE pilot study / 体力科学

This study examined the relationship between meeting the World Health Organization’s (WHO) 24-Hour Movement Guidelines for the Early Years and motor skills and cognitive function in preschool children. Participants were 4-year-old boys and girls in urban and rural areas (n=69). Physical activity was measured using a triaxial accelerometer (ActiGraph GT3X). Screen time and sleep duration were assessed via self-report by guardians. Meeting the 24-h movement guidelines was defined as: 10 to 13 h/night and nap of sleep, ≤1 h/day of sedentary screen time, and at least 180 min/day more than 1.5 METs. Motor skills were evaluated by the Ages & Stages Questionnaires, Third Edition (ASQ-3). Executive functions (shifting, visual-spatial working memory and inhibition) were evaluated by the Early Years Toolbox (Japanese translation). The prevalence of children meeting all three recommendations was 7.2% and 7.2% met none of the three recommendations. Children meeting physical activity recommendation had a better inhibition score compared to children meeting none of the recommendation (p=0.005). While, children not meeting the sleep recommendation had a better inhibition score compared to children meeting of the recommendation (p=0.042). In conclusion, meeting the physical activity or sleep recommendations were positively or negatively associated with the inhibition score. On the other hand, meeting none of the sedentary behaviour and the 3 recommendations was not associated with motor skills or cognitive function.

Physical activity in young children during outdoor and indoor free playing time and in physical education lessons in preschools / 体力科学

The primary aim of this study was to examine moderate-to-vigorous physical activity (MVPA) levels in preschool children during indoor and outdoor free playing time and during preschool physical education (PE) classes. The secondary aim was to determine which types of PE lessons are the best for increasing the percentage of MVPA. Physical activity during free playing time and in lessons was objectively evaluated with a triaxial accelerometer in preschool boys and girls (n = 281). Minutes of physical activity were categorized into physical activity ratios (PAR). MVPA was defined as PAR ≥3.0. Time tables and PE lesson types were recorded using logs kept by class teachers. The percentage of MVPA in outdoor free playing time (38.9±16.3%) was significantly higher than that of indoor free playing time (12.6±10.1%, p<0.001). On the other hand, there was no significant difference between the percentage in MVPA in outdoor free playing time and the percentage in PE lessons (n=94: 38.0±19.4%vs. 34.9±15.8%, ns). After adjustment for gender, age, body height and weight and preschool, there were not significantly different the percentage of MVPA among contents of PE lessons. In conclusion, children engaged in almost 30~40% MVPA during outdoor free playing time or PE. The children also engaged MVPA during indoor free playing time.

Erratum: Validation of Dietary Reference Intakes for predicting energy requirements in elementary school-age children

No abstract available.

Validation of Dietary Reference Intakes for predicting energy requirements in elementary school-age children

BACKGROUND/OBJECTIVES: Dietary Reference Intakes (DRI) for energy are derived from total energy expenditure (TEE) measured using the doubly labelled water (DLW) method. The objective of this study was to assess the validity of DRI for predicting the energy requirements of elementary school-age children. SUBJECTS/METHODS: The present study involved 25 elementary school-age children aged between 9 and 11 years. TEE was assessed by the DLW method, and the results were compared with the TEE predicted by the DRI equations in order to evaluate accuracy. RESULTS: The subjects' TEE measured by the DLW method was 1,925.2 ± 380.9 kcal/day in boys and 1,930.0 ± 279.4 kcal/day in girls, whereas resting energy expenditure was 1,220.2 ± 176.9 kcal/day in boys and 1,245.9 ± 171.3 kcal/day for girls. The physical activity level was 1.58 ± 0.20 in boys and 1.55 ± 0.13 in girls. The mean bias between the predicted and measured TEE was 12.6% in boys and −1.6% in girls, and the percentage of accurate predictions was 28.6% and 63.6%, respectively. In boys, the equation resulted in underprediction of TEE among the subjects having low TEE values, whereas there was overprediction among subjects having high TEE values as shown by the Bland-Altman plot. On the contrary, this proportional bias was not observed in girls. CONCLUSIONS: The findings of this study suggest that the DRI equation for energy could result in the overestimation of energy requirements in elementary school-age boys. In the case of girls, the equations could be accurate at the group level. However, the DRI appears to be invalid for individual girls, as more than one third of girls had their TEE inaccurately predicted. We recommend more studies for confirmation of these results.

Determinants and prediction methods of total energy expenditure – efforts at National Institute of Health and Nutrition in Japan – / 体力科学

The National Institute of Health and Nutrition, as a part of the National Institutes of Biomedical Innovation, Health and Nutrition at present, has put emphasis on energy metabolism research since its establishment in 1920. After 2000, the National Institute of Health and Nutrition introduced doubly labeled water method and human calorimeters and has also contributed to the establishment of energy requirements in the Dietary Reference Intakes for Japanese. Inter-individual differences in physical activity level are large and difficult to accurately evaluate. Therefore, various studies have been conducted using not only subjective methods such as questionnaire but also objective methods such as accelerometry. Moreover, determinants of total energy expenditure and physical activity have been investigated, including comparison of physical activity level between normal-weight and obese adults. New evidences on contribution of brown adipose tissue activity and diseases on energy metabolism have been obtained. In the near future, research to elucidate the mechanism of energy balance, more accurate and variety of assessment of physical activity, and examination from the viewpoints of chrono-nutrition and chrono-exercise are expected.

Relationship between outdoor playing time and moderate-to-vigorous physical activity for Japanese young children and correlates of physical activity / 体力科学

This study aimed to examine the relationship between daily outdoor playing time assessed using questionnaires for parents and daily moderate-to-vigorous physical activity (MVPA) using triaxial accelerometers for young children (213 boys: 5.8±0.6years and 193 girls: 5.9±0.6years). The study also examined the potential relationships between daily MVPA and exercise habits or familial and preschool factors which were assessed using questionnaires for parents. Daily MVPA was assessed using a triaxial accelerometer (ActivTracer, GMS) for 6 consecutive days, including weekdays and weekends. Outdoor playing time and percentage of outdoor playing time more than 60 min/day were 81±62 min/day and 64% for boys and 78±61 min/day and 62% for girls, respectively. Outdoor playing time was not significantly correlated with MVPA. The study found that no factors for MVPA, including exercise habits, were correlated with MVPA when adjusted for age, body height and log-body weight, except that MVPA for girls in kindergartens was higher than that in nursery schools. These findings suggest that the percentage of outdoor playing time more than 60 min/day was about 2/3 in young children. The questionnaire didn't reflect their MVPA. The factors used in the present study except for the preschool type for girls may not contribute to the time spent in MVPA in preschool children.

A new approach to assessment of energy expenditure during physical training / 体力科学

While the session-RPE (rating of perceived exertion) method can quantify training volume in athletes, this method is not able to evaluate energy expenditure (EE) during a training session. We developed an RPE-based activity record for assessing EE during athletic training, and we compared its results to those obtained using the flex-heart rate (flex-HR) method. The EE of nine female collegiate endurance runners was assessed by the RPE-based activity record and flex-HR methods during eight days in the normal training season. Subjects were asked to record their RPE in the record at 5-minute intervals, and to wear a HR monitor during training. All subjects also participated in an incremental treadmill exercise test, which was used to determine their RPE-EE and HR-EE regression equations. Although the RPE-based activity record significantly overestimated EE (RPE-activity record, 572 kcal/session; flex-HR method, 499 kcal/session; <i>p</i> = 0.031), it had high validity relative to the flex-HR method (intra-class correlation coefficient, 0.891; 95% confidence interval, 0.845–0.923) and there were no systematic errors in EE estimation between the two methods. Therefore, the RPE-based activity record can be used to assess EE during training in female runners. However, RPE-based activity record might overestimate EE for athletes who have more intermittent activities during training than endurance runners, because RPE takes more time for returning to the resting level than HR when the intensity of activity declines. Further research is needed to verify the validity of the RPE-based activity record for assessing EE during other sporting activities or measurement conditions, and to identify the factors affecting the degree of estimation error associated with this method.

Relationship of exercise at preschool and out of school and daily physical activity to physical fitness in preschool children in the Kanto region: a cross-sectional study / 体力科学

This study sought to examine the potential relationships of physical education (PE) participation at preschool and sports club (SC) participation out of school and daily physical activity (PA) measured objectively using a triaxial accelerometer, with physical fitness in preschool children. Physical fitness testing was used to measure both health-related and skill-related parameters of fitness in 191 Japanese preschoolers in the Kanto region (94 boys and 97 girls, 5.6 ± 0.6 years). Daily PA was assessed using a triaxial accelerometer (ActivTracer, GMS) for 6 consecutive days, including weekdays and weekend days. PE and SC participation was assessed using questionnaires for preschool teachers or parents of subjects, respectively. All health-related and skill-related physical fitness and total Z-score were correlated with time spent with physical activity ratio (PAR)≧4 when adjusted for age, sex, body height and weight. In addition, greater grip strength was associated with PE participation at preschool, and 25 m run speed was associated with SC participation, also. However, 25 m run speed was negatively associated with PE participation. These findings suggest that daily PA may contribute to the development of both health-related and skill-related fitness in preschool children, although further research on the cause-effect relationship is needed. Moreover, participation in a SC may contribute to the development of running speed.

Role of epoch length on daily locomotive and non-locomotive physical activity using a triaxial accelerometer and relationships with obesity in adults / 体力科学

The aims of the present study were to examine the role of epoch length (time sampling interval) on locomotive and non-locomotive physical activity (PA) estimates and the relationships with obesity in healthy adults in each sex. Subjects were 308 Japanese women and 183 men aged 20-to-64years old. Time in locomotive and non-locomotive light PA (2.0 ~ 2.9METs; metabolic equivalents) and moderate-to-vigorous PA (MVPA, 3 METs or more) and step counts were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare Co., Ltd) presented in 60s and 10s epochs. Body mass index (BMI) by height and body weight was calculated. There were significant differences between results by epoch lengths in both locomotive and non-locomotive PA. In particular, the difference was remarkable for non-locomotive PA. Time in each MVPA for women and men when presented in 10s epochs were significantly higher. Time in total MVPA was different by nearly 30min for women and nearly 20min for men. Moreover, time in non-locomotive light PA when presented as 60s epochs was significantly higher in both women and men than that when presented as 10s epochs, and time in total light PA showed an obvious difference of nearly 50min higher in 60s epochs for women. Conversely, the relationships between PA with 60sec and 10sec estimates and BMI were weak, even though over half of PA variables showed significant correlations. These findings suggest that non-locomotive PA evaluated by the triaxial accelerometer was obviously affected by epoch length. The finding also showed gender differences.

Contribution of non-locomotive activity to habitual physical activity in Japanese workers / 体力科学

Pedometers are frequently used to measure habitual physical activity (PA). However, non-locomotive PA may constitute a substantial part of total PA in workers engaged in certain occupations. The purpose of the present study was to examine the relative contribution of non-locomotive PA to total habitual PA in Japanese workers. Subjects were 177 Japanese males and females. Occupations of the subjects were preschool (kindergarten and nursery school) teachers, salespersons, drivers, licensed cooks, security guards, housewives, garbage collectors and office workers. Light PA, moderate-to-vigorous PA (MVPA) and step counts were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare Co., Ltd), which allowed for an accurate discrimination between locomotive and non-locomotive PA. The non-locomotive component of MVPA predominated in licensed cooks and garbage collectors, while security guards displayed more locomotive MVPA. The non-locomotive component of light PA predominated in preschool teachers, salespersons, licensed cooks and housewives, while security guards displayed more locomotive light PA. Relative contributions of non-locomotive PA were different among occupations. The present study suggests that locomotor measurements alone might substantially underestimate habitual PA in workers engaged in certain occupations (e.g., licensed cooks and garbage collectors).

Daily steps corresponding to the reference quantity of physical activity of Exercise and Physical Activity Reference for Health Promotion 2006 (EPAR2006) assessed by accelerometer / 体力科学

The purpose of this study was to determine daily steps corresponding to the reference value for the quantity of Physical Activity and Exercise for Health Promotion 2006 (23 METs·h/wk) considering non-locomotive activities. Two hundred and thirty one men and 224 women wore a tri-axial accelerometer for two weeks. We analyzed the data in each age group (young (less than 40 years), middle-aged (40 to 59 years), and elderly (60 years or more) groups), also. There were significant relationships between daily steps and locomotive activity (r = 0.762 to 0.820, p < 0.001) and total (locomotive and non-locomotive) physical activity (r = 0.706 to 0.824, p < 0.001) with intensity of 3 METs or more in all groups. The daily steps corresponding to 23 METs·h/wk, calculated using regression lines between the daily steps and total physical activities with intensity of 3 METs or more in men and women were 6,534 steps/d and 6,119 steps/d. On the other hand, the daily steps corresponding to 23 METs·h/wk, calculated using regression lines between the daily steps and locomotive activities with intensity of 3 METs or more in men and women were 7,888 steps/d and 8,584 steps/d. These results suggest that non-locomotive activity should also be taken into consideration in the case of assessment of a daily physical activity.

COMPARISON OF LEVELS OF DAILY PHYSICAL ACTIVITY BETWEEN JAPANESE PRESCHOOL CHILDREN ENROLLED IN KINDERGARTENS AND NURSERY SCHOOLS / 体力科学

Most Japanese preschool children attend either kindergartens or nursery schools, each providing a distinct environment for children, and the difference between these may be associated with varying patterns of physical activity (PA). The purpose of the present study is to compare the levels of PA in Japanese preschool children enrolled in kindergartens to those enrolled in nursery schools by using triaxial accelerometry (ActivTracer, GMS). PA was assessed using a triaxial accelerometer and daily steps were captured using a uniaxial accelerometer for 6 consecutive days, including weekdays and weekends. Subjects were 157 four- to six-year-old Japanese children attending kindergartens or nursery schools. Moderate-to-vigorous physical activity (MVPA) and step counts were 107 (±34) min/day and 13,567 (±2,725) steps/day respectively for kindergartens, and 97 (±30) min/day and 12,526 (±2,884) steps/day respectively for nursery schools. MVPA and step counts were significantly higher for children enrolled in kindergartens than those enrolled in nursery schools. Although PA on weekdays did not differ significantly, physical activity level, MVPA, and step counts on weekends were significantly higher for children enrolled in kindergartens than those enrolled in nursery schools. In addition, we observed large variability in PA among children enrolled in kindergartens, and relatively little variability among children enrolled in nursery schools. The results suggest that children in nursery schools exhibit less engagement in moderate PA than children in kindergartens, and the difference is more pronounced on weekends. Additionally, we found that PA patterns in young children enrolled in kindergartens may vary greatly.

UNIAXIAL ACCELEROMETER FOR ASSESSING PHYSICAL ACTIVITY IN 5- TO 6-YEAR-OLD CHILDREN / 体力科学

The accuracy of a uniaxial accelerometer for assessing physical activity in preschool-aged children was assessed by using an indirect calorimeter which provides the physical activity ratio (PAR) for free living activities. Subjects were 5- to 6-yr-old Japanese girls and boys (n=24, 6.1±0.3 years). PAR was assessed for nine activities (lying down, watching a video while sitting and standing, line drawing for coloring-in, playing with blocks, walking, stair climbing, ball toss, and running) using the Douglas bag method. “Exercise intensities” were recorded with the uniaxial accelerometer (Lifecorder EX ; Suzuken Co. Ltd, Nagoya, Japan). PARs were also predicted by using the equations presented by Higuchi et al. (2003) and Kumahara et al. (2004). Significant correlation was observed between “exercise intensities” as measured by the uniaxial accelerometer and PAR for all activities (r=0.827). Predicted PAR values for walking and running were overestimated according to the equations. On the other hand, PAR values for stair climbing and ball toss were underestimated. These findings indicate that although the uniaxial accelerometer may help in evaluating daily physical activity in preschool-aged children, its use as a proxy measure of PAR based on the above equations may be limited.

Effects of bone mineral content and density on accuracy of body fat measurement by underwater weighing / 体力科学

Underwater weighing is based on the assumption that fat-free body density is roughly constant among humans. This assumption should be examined, because fat-free body density may in fact depend on the bone mineral and water contents of the body, with fat excluded. The purpose of this study was to investigate the effects of bone mineral content (BMC) and density (BMD) on the accuracy of body fat measured underwater. The subjects were 12 young men (25.1±3.7 years, mean ± SD), some of whom were trained athletes. BMC and BMD were measured by dual-energy x-ray absorptiometry (DXA), as was body fat, as a percentage of body weight; this method is not based on the assumption that fat-free body density is the same in different individual. Body fat as a percen tage of body weight was measured underwater, also. Body fat measured by DXA was significantly correlated with that found by underwater weighing (r = 0.83, p<0.01), as expected, but the mean body fat found by DXA was 4.3% higher. The differences between results by the two methods for individuals were from -11.5% to 2.7%, and the differences were negatively correlated with BMC/fat-free weight (FFW ; r=-0.82, p < 0.01) and BMD (r=-0.85, p<0.01) . Fat-free body density ranged from 1.097 to 1.111 g/cm<SUP>3</SUP>because BMC/FFWs varied with the individual. We concluded that individual differences in BMC/FFW and BMD affected the fat-free body density. The variations in fat-free body density would give rise to systematic errors in body composition measured underwater.