Intensity and Bouts of Physical Activity and Physical Activity Level in Pre-adolescent Children: 1407 Board #60 June 2, 9: 00 AM - 10: 30 AM.

Increasing pre-adolescent children’s physical activity level (PAL) is an important way to prevent adolescent obesity. It is therefore necessary to investigate the types of physical activity of pre-adolescent children that are associated with PAL, with particular attention paid to the intensity and bouts of physical activity. PURPOSE: The objective of this study was to elucidate the intensity and bouts of physical activity associated with PAL in pre-adolescent children. METHODS: This study was a cross-sectional study of 42 elementary school children aged 10 to 11 years old (26 boys, 16 girls). We defined PAL as the total energy expenditure as measured using the doubly labeled water (DLW) method, which is the gold standard for the measurement of field metabolic rate, divided by the basal metabolic rate. In order to measure the intensity and duration of physical activity performed during DLW measurement, we used uniaxial accelerometers to evaluate sedentary behavior (SED), light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA). MVPA was categorized by bouts of increasing duration: Sporadic (<4 min), short (≥4 and <10 min), and medium-to-long bouts (≥10 min). Partial correlation adjusted for sex and the accelerometer wearing time was used to analyze the association between PAL and the physical activity variables. RESULTS: SED showed a significant negative association with PAL (r=-0.409, p<0.01), and LPA showed a significant positive association with PAL (r=0.329, p<0.05). Although no significant association between total MVPA and PAL was observed, medium-to-long bouts of MVPA showed a significant positive association with PAL (r=0.322, p<0.05). CONCLUSION: Although the correlations were not strong, these results suggest a negative relationship between SED and PAL, and also a positive relationship between LPA and medium-to-long bouts of MVPA and PAL among pre-adolescent children.