Influence of gender, BMI and Hispanic ethnicity on physical activity in children.

OBJECTIVE: The purpose of this study was to examine the association between overweight status and physical activity (PA) among gender and ethnic (Hispanic vs. non-Hispanic) sub-groups in elementary school-age children.
METHODS: PA was assessed over five days using the Actigraph accelerometer in 169 fourth grade students (mean age 9.4 years; 50% female; 63% Hispanic; and 43% overweight, defined as body mass index, BMI > or = 85th percentile for age and gender) from four elementary schools in Los Angeles County, California.
RESULTS: In the total sample, boys and normal weight students had higher levels of total PA (counts per minute, cpm; p<0.05). Boys spent less time in sedentary PA (p=0.02) and more time in combined moderate to vigorous PA (MVPA, p=0.01). There was a significant gender, ethnicity, and overweight interaction for total PA and MVPA (both p<0.01). MVPA and counts per minute were significantly lower in overweight non-Hispanic girls and Hispanic boys (p<0.05) and marginally lower in overweight non-Hispanic boys (p=0.10) when compared with non-overweight students, while overweight Hispanic girls were more physically active than Hispanic non-overweight girls, though the difference was non-significant (p>0.05).
CONCLUSIONS: Data from the present study does not consistently support the prevailing hypothesis that overweight subjects engage in less PA. Results show overweight students engage in less PA than non-overweight students, with the exception that non-overweight Hispanic girls do not engage in more PA than their overweight peers. These results suggest the need for further investigation into the role that ethnicity and overweight status plays in PA levels, particularly among ethnic and gender sub-groups.