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 >or=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.