Translating Physical Activity Recommendations for Overweight Adolescents to Steps Per Day

Background: Steps/day guidelines For children aged 12 years and under are 12,000 to 16,000. There are limited report,, in the literature on how many steps/day adolescents need to meet the 60-minutes/day moderate-to-vigorous physical activity (MVPA) recommendation. This Study aimed to determine the steps/day that correctly classifies adolescents as meeting the 60-minute recommendation using objective measures. Methods: This analysis Used data from 40 overweight (BMI M=31.5, SD=5.3) adolescents enrolled between 2005 and 2006 in a Study to lose weight. Participants were aged 11 to 16 years (M=13.2, SD=1.2), 70.0% girls, and 52.6% non-Hispanic white, 23.7% Hispanic, and 23.7% other race/ethnicity. Participants wore an Actigraph accelerometer for up to 7 days that measured accelerations and Step Counts simultaneously. The age-adjusted Freedson equation was used to estimate physical activity-intensity minutes. Two criteria were used to define MVPA (3/6 and 4/7 METs). Analyses were conducted between 2008 and 2009. Results: Based on accelerometer data, approximately 48% and 10% of adolescents met the MVPA recommendation depending on the MVPA criteria. Adolescents who met phyiscial activity recommendation had higher MVPA min/day (p<0.001) and higher step counts (p<0.001), after adjusting for gender, age, and ethnicity. Receiver operating characteristic (ROC) curve analyses found that 9930 steps produced 0.84 sensitivity and 0.81 specificity (area under the curve [AUC] =0.89) and 11,714 steps produced 0.75 and 0.81 specificity (AUC=0.94) for meeting the recommendation using the 3/6 and 4/7 criteria, respectively. Conclusions: Depending on the MVPA criteria used, these data Suggest that overweight adolescents are likely to meet national NATA recommendations if they accumulate between 10,000 and 11,760 steps per day. (Am J Prev Med 2009;37(2):137-140) C 2009 American journal of Preventive Medicine