Physical activity of children and youth in Nova Scotia from 2001/02 and 2005/06.

OBJECTIVES: This paper reports on physical activity of students in grades 3, 7, and 11 from two surveillance studies (from 2001 and 2005). METHODS: Randomly selected students (Study1 n=1730; Study2 n=2341) from randomly selected schools in Nova Scotia participated. Physical activity was measured for seven consecutive days using Actigraph accelerometers. Descriptive statistics were calculated for moderate, hard, and very hard intensity, and total minutes of physical activity. Between study, grade, and sex differences were determined using univariate Analyses of Variance. RESULTS: Students in Study2 were significantly less active (mean [SD]=531.0 [392.3] min/week) than Study1 (662.2 [495.1] min/week). Girls were significantly less active (525.4 [419.1] min/week) than boys (657.1 [460.3] min/week). Students in grade 11 were significantly less active (225.2 [171.1] min/week) than students in grade 7 (457.5 [227.2] min/week) who were significantly less active than students in grade 3 (1038.4 [387.6] min/week). A significant study-grade interaction indicated that compared to students in grades 7 and 11, the level of physical activity in students in grade 3 was considerably lower in Study2 compared to Study1. CONCLUSIONS: Given the lower level of physical activity found in Study2, efforts at informing public policy and strategies that promote physical activity in children and youth should be made.

Are overweight students in Grades 3, 7, and 11 less physically active than their healthy weight counterparts?

OBJECTIVE: This study compared the accumulated minutes of objectively measured physical activity in 1,790 boys and girls in Grades 3, 7, and 11 classified as healthy weight, at risk of overweight, and overweight. METHODS: Height and weight were measured and body mass index calculated. Minutes of sedentary, light, moderate, hard, and very hard physical activity were obtained from a seven-day measurement of physical activity using an accelerometer (Actigraph, mode 7164; MTI). RESULTS: In Grade 3, boys (p=0.000) and girls (p=0.012) classified as overweight obtained significantly fewer minutes of very hard physical activity compared with their healthy weight counterparts. Boys in Grade 7 considered overweight obtained significantly fewer minutes of hard (p=0.002) and very hard physical activity (p=0.006) compared with boys who were a healthy weight. There were no significant differences in minutes of sedentary, light, moderate, hard, or very hard intensity physical activity in the boys and girls in Grade 11, who were considered a healthy weight, at risk of overweight, or overweight. CONCLUSIONS: Weak and inconsistent support was provided for the notion that boys and girls classified overweight are less physically active than their healthy weight counterparts.

Physical activity and body mass index in grade 3, 7, and 11 Nova Scotia students.

PURPOSE: This study examined the average time spent in moderate or more intense physical activities according to weight status in randomly selected Nova Scotia students. METHODS: A total of 1653 students participated in this study: 575 in grade 3, 558 in grade 7, and 520 in grade 11. Physical activity was measured for seven consecutive days using MTI accelerometers. Activity counts were classified according to moderate (3-5.9 METs), hard (6-8.9 METs), and very hard (>9 METs) intensities. Height and weight were measured and body mass index (BMI) calculated. Centers for Disease Control and Prevention BMI criteria for age and sex were used to classify the students as normal weight (< or =85th percentile), at risk of overweight (>85th and < or =95th percentiles), and overweight (>95th percentile). ANOVA was used to compare the average time spent in moderate, hard, and very hard physical activities according to BMI status in boys and girls in grades 3, 7, and 11. RESULTS: Although age and sex differences existed, there were no significant differences in the average time spent in moderate or more intense physical activities in the BMI groups. CONCLUSION: Further research is warranted to elucidate the factors surrounding the relationship between physical activity and BMI in children and youths.