Step-count Guidelines For Sixth Grade Students Using Receiver Operating Characteristic And Accelerometry

Abstract

Identification of children with inadequat e levels of physical activity is important for surveillance and screening purposes. Current physical activity guidelines are based on duration, frequency, and intensity of physical activity. The CDC recommends a minimum of 60-minutes of moderate physical activity daily. However, use of existent guidelines may not be easily understood by children, adolescents, or their parents. Pedometers are an attractive alternative to identify children not reaching adequate levels of physical activity. Adapting current guidelines to step-counts can simplify physical activity guidelines. PURPOSE: The purpose of this study is to measure the diagnostic accuracy of pedometer step-counts and establish step-count guidelines for six grade students. METHODS: Seventy-seven sixth grade students participated in the study. They wore a pedometer and an accelerometer at the waist level during one full day. Receiver Operating Characteristic curves were used to determine the diagnostic accuracy of step-counts and gender specific step-count guidelines. RESULTS: The area under the curve for boys (AUC=.88) and girls (AUC=.90) indicate good diagnostic accuracy of step-counts to discriminate among sixth grade students with adequate and inadequate levels of physical activity. To reach adequate levels of physical activity, 12,650 and 15,100 steps/day are recommended for sixth grade girls and boys respectively. CONCLUSIONS: To our knowledge, this is the first study to show the diagnostic accuracy of step-counts. Step-count guidelines suggested in this study can be an important tool for identifying children not reaching adequate levels of physical activity. Future studies should focus on the development of age specific guidelines for a broader developmental spectrum.