ASSESSING DAILY PHYSICAL ACTIVITY IN ELEMENTARY SCHOOL STUDENTS USED BY ACCELEROMETER / 体力科学

The purpose of present study was to examine validity of accelerometer (Lifecorder ; LC) and to assess the free-living physical activity (PA) in Japanese elementary school students used by LC method. Firstly, to examine validity of LC, twelve children, aged 11.2±1.0 years, were measured total energy expenditure (TEE) by doubly labeled water method and resting energy expenditure (REE) by the expired gas analysis. Physical activity energy expenditure (PAEE) is calculated as 0.9 TEE minus REE. At the same time, PA was evaluated by both daily walk count (WC) and vigorous activity time (LC7-9) using LC method. PAEE per 1 kg body weight significantly correlated with WC (r=0.785, p<0.005) and LC7-9 (r=0.828, p<0.001). Secondly, 140 boys and 167 girls, aged 8-11 years were measured PA by LC method. WC and LC7-9 each were 13000-18000 counts and 16-32 minutes in week-day, and 8000-12500 counts and 8-18 minutes in week-end. PA analyzed by MANOVA were significantly higher in boys than in girls, and lower in week-end than in week-day, and decreased in proportion as grade. Present study suggests that LC method is a good measure of PA in free-living condition for elementary school students.

VALIDITY OF METHODS TO MEASURE TOTAL ENERGY EXPENDITURE OF BASEBALL PLAYERS IN JAPANESE HIGH SCHOOL / 体力科学

The purpose of this study was to assess the validity of activity record (AR), accelerometer (AC) and heart rate (HR) methods in comparison with the doubly-labeled water (DLW) method as the criterion measure of total energy expenditure (TEE) in high school students undergoing vigorous activities. Twelve baseball players in Japanese high school (16.5±0.5 yrs) were monitored for seven consecutive days. TEE values obtained over a 3-day-period by AR, AC and HR were simultaneously validated against TEE measured by DLW over a 7-day-period. TEE value measured by DLW was 4922±391 kcal/day. The Physical activity level (PAL=TEE/BMR (basal metabolic rate)) was 2.66±0.14. TEE estimated by AR, AC and HR was significantly different from DLW, with mean differences of -13.9±6.5%, 35.3±3.6% and 31.6±23.9%, respectively. However, TEE estimated by AC and AR significantly correlated with that measured by DLW (r=0.73, r=0.70, p<0.05, respectively). The limits of agreement between DLW and AR, AC and HR were from -1350 kcal/d to -21 kcal/d, -2293 kcal/d to -1192 kcal/d, and 3875 kcal/d to -797 kcal/d respectively. AC was superior to the other methods. However, the limits of agreement in AR were similar to AC. These data suggest that on accuracy and precision, AR would be superior to the other two for predicting TEE in high school students undergoing vigorous activities. However, AC has the advantages being able to examine patterns of activity over long periods of time without interfering with normal movement and the ability to store data continuously over long periods of time. Therefore, it was suggested that, simultaneously, the AR and AC methods are accurate predictors of TEE and patterns of activity while undergoing sports vigorous activities.

MEASUREMENT OF TOTAL ENERGY EXPENDITURE IN JAPANESE FIREFIGHTERS UNDER NORMAL WORKING CONDITION USING THE DOUBLY LABELED WATER METHOD / 体力科学

This study examined total energy expenditure (TEE) of Japanese firefighters under normal working conditions, and also evaluated several field methods for measuring TEE in comparison with the doubly labeled water (DLW) method. Ten male subjects belonging to Tokyo metropolitan firefighters departments, aged 30.0±2.8 yrs (mean±SD), were monitored for five consecutive days. While TEE was assessed by an accelerometer (AC) and activity records (AR) in additoin to DLW, energy intake (El) was evaluated by dietary record. There were three emergency calls over the assessment period, but no real operation of fire suppression. TEE obtained by the DLW method (4009±611 kcal/d) was significantly higher than that estimated by AC (2531±186 kcal/d) or AR (3704±476kcal/d) ; but significantly correlated with AR (r=0.876, p<0.01) . El (3539±286 kcal/d) showed no significant relationship with DLW. These results suggest that compared with AC, AR would be more feasible for estimating TEE of firefighters, who perform special activities carrying heavy equipment. The mean value of physical activity level (PAL) (2.2±0.3) indicates that firefighters can be categorized as heavy workers like soldiers or policemen.

Comparative study of total energy expenditure in japanese men using doubly labeled water method against activity record, heart rate monitoring, and accelerometer methods / 体力科学

The purpose of this study was to examine total energy expenditure (TEE) in Japanese men under free-living conditions using various field methods, and compare these methods with the doubly labeled water method (DLW) . Ten Japanese men, aged 24.2±1.8 (mean±SD) yrs, were studied for 14 consecutive days. TEE was assessed by DLW, activity record method (AR ; using relative metabolic rate and calculated basal metabolic rate), heart rate monitoring methods (Two-line and FLEX-HR methods), and accelerometer method (AC) . Energy intake (EI) was also evaluated over the same period. Although TEE estimated by AR (2730±139 kcal⋅day<SUP>-1</SUP>), Two-line (2925±433 kcal⋅day<SUP>-1</SUP>), and FLEX-HR (2949±506 kcal⋅day<SUP>-1</SUP>) did not differ significantly from the TEE determined by DLW (2910±524 kcal⋅day<SUP>-1</SUP>), there was no significant relationship between each of these methods and DLW. In addition, El (2963±482 kcal⋅day<SUP>-1</SUP>) and TEE determined by DLW were similar, and there was a significant correlation (r=0.809, P<0.01) . Compared with DLW, AC (2697±541 kcal⋅day<SUP>-1</SUP>) underestimated TEE at the group level ; however, AC was the only method to show a significant correlation with DLW (r=0.871, P<0.001) . Therefore, it seems possible that AC would accurately estimate TEE at the individual level by improving both the instrument and its methodology.