Assessment of diet and physical activity of brazilian schoolchildren: usability testing of a web-based questionnaire.

Background: Information and communication technology (ICT) has been used with increasing frequency for the assessment of diet and physical activity in health surveys. A number of Web-based questionnaires have been developed for children and adolescents. However, their usability characteristics have scarcely been reported, despite their potential importance for improving the feasibility and validity of ICT-based methods.

Longitudinal and cross-sectional changes in active commuting to school among Brazilian schoolchildren.

Objective: The objective of the study is to evaluate cross-sectional and longitudinal changes in children's commuting to school in a representative sample of a Brazilian city.

Methods: Two school-based studies were carried out in 2002 (n=2936; 7-10 years old) and 2007 (n=1232; 7-15 years old) in Florianopolis, Brazil. Cross-sectional data were collected from children aged 7 to 10 years in 2002 and 2007.