[Reliability of a questionnaire for measuring physical activity and sedentary behavior in children from preschool to fourth grade].

INTRODUCTION: International recommendations for physical activity and time spent in sedentary behaviors for children in their early years require the availability of measuring instruments with psychometric properties that allow for the assessment of population dynamics and interventions to improve health.
OBJECTIVE: To evaluate the reliability of a questionnaire to measure physical activity and sedentary behaviors in children from preschool to fourth grade.
MATERIALS AND METHODS: One hundred and eight parents answered the questionnaire. The instrument included socio-demographic variables, as well as those associated with physical activity, including time walking to school, organized sports and playtime activities. Sedentary behaviors included motorized transport to school, reading and "screen time", sleeping and extracurricular courses. Internal consistency, reproducibility and agreement were evaluated using Cronbach's alpha coefficient, the Intraclass Correlation Coefficient (ICC) and the Bland and Altman limits of agreement method, respectively.
RESULTS: Internal consistency for physical activity ranged from 0.59 to 0.64, and for sedentary behaviors between 0.22 and 0.34. The highest reproducibility was found for walking to school and time spent on this (kappa=0.79, ICC 0.69), and organized sports, and time on this activity (kappa=0.72, ICC 0.76). Among sedentary behaviors, motorized transport to school and computer use showed kappas of 0.82 and 0.71, respectively; additionally, the time spent on these behaviors showed an ICC of 0.8 and 0.59, respectively. We found limits of agreement between moderate and good for reading time, napping, extracurricular courses, computer and console use.
CONCLUSION: The questionnaire provided reliable information on the physical activity and sedentary behaviors in children under 10 years of age and could be used in other Latin American countries.