Methodological aspects by accelerometer-assessment of physical activity in 7-10 years old children: a systematic review

INTRODUCTION: Previous studies have shown the importance of quantifying physical activity and its association to health-disease process. This task is not easy, especially in children, because it represents a multidimensional construct that involves leisure activities, educational environment, linked to occupation and transportation. Accelerometers have been used in epidemiological studies with adults and children when there is interest in assessing physical activity. The aim was to explore methodological aspects by accelerometer-assessment of physical activity among children aged 7 to 10 years old.

METHODS: Systematic review of studies selected according to predefined steps: inclusion criteria studies; search strategies, quality assessment criteria of identified studies; information to be extracted. Among the interest features, may be mentioned those related to accelerometers technology, age group and outcome measures.  

RESULTS: We found 872 papers in four databases: PubMed, Embase, SPORTDiscus, Lilacs. Sixty-eight studies had methodological quality and were included in the review. The prevailing equipment was the uniaxial accelerometer Actigraph® (Models: GT1M, 7164), frequently placed to the right hip, seven days a week, with epochs lasting 60 seconds, considering valid information obtained during three or more days of data collection and presence of a large variety of cutoff points for intensity levels and physical activity outcomes.

CONCLUSIONS: Accelerometers are used in epidemiological researches for the assessment of physical activity considering counts as measures, in spite of there is no easy understanding about it so far, once the equipment was built to "translate" movements performed in one or more plans of frequency, intensity and duration of the activity. Methodological aspects that restrict comparison between studies: different brands and models, fixation body sites, as well as different observation number days, wide age group, different epochs duration and cutoff points. In addition, we suggest more methodological studies to elucidate the accelerometers applicability in children aged 7 to 10 years.