Physical Activity across Body Composition and Sex in Low Income Mexican and White American Youth

Abstract

PURPOSE: The purpose of this study was to determine whether physical activity (PA) differs across different body composition and sex in low income Mexican and White youth in the United States. METHODS: Participants were 195 youth (78 boys and 117 girls with a M±SD age of 14.8±1.5 years). Approximately 51% were Mexican American and 49% were White youth. PA was assessed using a piezoelectric pedometer with a moderate to vigorous physical activity (MVPA) timer. Participants wore the pedometers for 7 days and recorded daily time worn on a PA log. MANOVA was used to determine the interactions of race (White vs. Mexican), sex (M vs. F), BMI classification (<85th percentile vs. ≥85th percentile), and waist circumference (WC) classification (<90th percentile vs. ≥90th percentile) on average steps/day and average MVPA/day for the weekend (WE) and weekdays (WD). RESULTS: Results of the MANOVA indicated a significant three-way interaction between race, sex, and BMI categories for average MVPA time on the WE (p=0.034). Then a 2x2 factorial ANOVA by sex was performed using race and BMI categories as the factors. No significant interaction was found, but the males showed a significant difference between overweight and normal weight categories, with the normal weight participants performing more WE MVPA, but no difference was found between the two races. For the females, a significant main effect was found for race, with white showing higher activity than Mexican on the WE, but no difference was found between BMI categories. The MANOVA also indicated significant main effect of race for average MVPA time on the WE (p=0.002) and WD (p=0.050), showing higher MVPA in White as compared to Mexican participants. The MANOVA also showed a main effect of sex for all dependent variables (WE steps/day p<0.001, WD steps/day p=0.001, WE MVPA p=0.008, WD MVPA p=0.008), with males taking more steps/day and showing higher MVPA for both WE and WD. Chi square showed observed number of overweight youth was significantly different than expected in all groups (p<0.01). CONCLUSIONS: White were more active than Mexican American youth with Mexican American girls least active, although low PA was seen regardless of race and sex. Effective interventions to increase daily PA for low income and ethnic minority youth in the United States must become a higher public priority.