Activity Levels for Four Years in a Cohort of Urban-Dwelling Adolescent Females.

PURPOSE: Evidence suggests that female adolescents and those living in urban environments may have lower physical activity (PA) levels compared with their peers. Yet few studies report PA for urban adolescent females, and there is no consensus regarding potential causes for low PA in this subgroup. We examined PA levels, in a large, diverse cohort of 14- to 17-yr-old urban-dwelling females and assessed the effect of socioeconomic, personal, and neighborhood/environmental factors on PA. METHODS: One week of time-stamped step count data were collected on 926 girls from the Pittsburgh Girls Study at four annual visits. Valid recordings (worn at least 10 h on 3+ d) were examined and compared with normalized step count values from a U.S. population-representative sample. Relationships between important covariates and average steps per day were examined with regression models. RESULTS: Adjusted mean ± SD step counts per day at baseline were 5614 ± 2434 after controlling for important covariates with less than 6% of girls achieving at least 10,000 steps per day. The girls from the Pittsburgh Girls Study accrued ~45% of their steps during school hours. Age-specific median step counts per day for study participants were similar to the 25th percentile of U.S. population normalized values and did not significantly change during follow-up. Non-Hispanic African American race/ethnicity was associated with higher average step counts per day; obesity and a recent childbirth were associated with lower average step counts per day. CONCLUSIONS: Step counts in this cohort of urban adolescent girls were considerably lower than expected for U.S. adolescent females. Targeted efforts to improve PA levels in urban youth should consider the importance of school-based activity while increasing PA opportunities outside of school.

Measuring Physical Activity and Sedentary Behavior in Youth with Type 2 Diabetes.

BACKGROUND: Lifestyle interventions that encourage increasing physical activity (PA) and losing weight are critical for overweight and obese youth with comorbid conditions. Assessing PA within such lifestyle intervention efforts requires measurement tool(s) that are both accurate and appropriate for these youth. This research compares PA levels and sedentary behavior in an ethnically diverse cohort of overweight/obese youth with type 2 diabetes using both accelerometry and a questionnaire previously validated in the general youth population. METHODS: Spearman's correlations were used to compare time spent sedentary and in different PA intensities between a questionnaire, the three-day PA recall (3DPAR), and an objective PA measure, the ActiGraph accelerometer, in 236 overweight/obese youth with diabetes. RESULTS: Spearman correlations between 3DPAR and accelerometer results for total PA were small and not significant (rho = 0.11, p > 0.05 for males and females). Correlations for specific PA intensities (moderate/vigorous and light) were also small and not significant. Sedentary time between instruments was significant, but weakly correlated in females (rho = 0.19, p < 0.05), but not in males (rho = 0.07, p = 0.48). CONCLUSIONS: Subjective PA measures validated in the general youth population may not be the best method for differentiating levels of movement in overweight/obese youth with type 2 diabetes, who spend most of their time in light-intensity activity and sedentary pursuits with little or no time spent in moderate/vigorous-intensity activities. Objective measures such as accelerometers that can capture the lower end of the movement scale are likely the more appropriate measures under these conditions.