Objectively Measured Physical Activity in Urban Alternative High School Students

Introduction: Alternative high school (AHS) students are an underserved population of youth at greater risk for poor health behaviors and outcomes. Little is known about their physical activity patterns. Purpose: The purpose of this study was to describe 1) physical activity levels of students attending alternative high schools (AHS) in St. Paul/Minneapolis, MN, and 2) compliance with wearing a physical activity accelerometer. Methods: Sixty-five students (59% male, 65% <18 yr old, 51% African American, 17% Caucasian, 32% mixed and other) wore an accelerometer during all waking hours for 7 d as part of the baseline assessment for a school-based physical activity and dietary behavior intervention. Accelerometer data were reduced to summary variables using a custom software program. Compliance with wearing the accelerometer was assessed by the number of days with >= 10 h of data. Accelerometer counts per minute and minutes spent in moderate-to-vigorous physical activity (MVPA) were calculated. Results: Students averaged 323 +/- 143.0 counts.min(-1) and 51 +/- 25.5 min.d(-1) of MVPA. Minutes of MVPA.d(-1) were greater on weekdays compared with the weekend (52 +/- 27.3 vs 43 +/- 39.7 min.d(-1), respectively; P = 0.05). However, students wore the accelerometer less on the weekends (weekdays 17.2 +/- 3.0, weekend = 14.9 +/- 6.8 h.d(-1)) Expressing minutes of MVPA as a percentage of the number of minutes of available data. students spent approximately 5% of their time in MVPA on weekdays and weekends. Forty-five percent of students had 7 d of data, 51% had 4-6 d, and 5% had fewer than 4 d. On average, students wore the accelerometer for 17 +/- 3.2 h.d(-1) (range = 12.0-23.8 h.d(-1)). Conclusion: Compliance was high (95% of students provided at least 4 d of data), and physical activity was relatively low representing a vulnerable population in need of further study and intervention.