Influência do número de dias e de horas válidas de uso do acelerômetro na estimativa do nível de atividade física em pré-escolares de Recife, Pernambuco, Brasil

Abstract

Influence of number of days and valid hours using accelerometry on the estimates of physical activity level in preschool children from Recife, Pernambuco, Brazil Abstract -A few studies have proposed the number of hours/day and the number of days of monitoring that should be completed to obtain good quality accelerometry data for preschool children. The aim of this study was to analyze how the estimates of physical activity levels and sample profiles (demographic and anthropometric data) vary according the use of different criteria to define valid monitoring periods. Children (n=180) aged three to five years were randomly selected among participants from a longitudinal study performed in Recife, Brazil. Children wore a GT1M Actigraph accelerometer on the right waist during a period of seven days, including the weekend days, using 15 s epochs. A total of 176 children were included in the study (52.8% boys; mean age of 4.3 years [s=0.8]). Using the criterion of 10+ hours/day of wearing time to define a valid monitoring day, 67.0% (n=118) and 36.9% (n=65) of the children showed 3+ and 5+ valid days, respectively. When the criterion of 5+ hours/day was used, the time spent in moderate activity was approximately 10 minutes shorter than when the criterion of 10+ hours/day was used. The criterion of 10+ hours/day for defining a valid monitoring day leads to a sample size reduction and the criterion of 5+ hours/day underestimates the moderate activity level. Key words: Accelerometry; Exercise; Health behavior; Physical activity; Preschool. (52,8% meninos; idade média de 4,3 anos [s=0,8] Resumo -Poucos estudos têm pesquisado acerca do número de horas/dia e o número de dias de monitoramento que devem ser completados para se obter boa qualidade de dados por meio do uso de acelerômetros para crianças pré-escolares. O objetivo deste estudo foi analisar a influencia em se usar diferentes critérios para definir períodos de monitoramento válido na estimativa nos níveis de atividade física e no perfil da amostra. Crianças (n=180) com idade de três a cinco anos

Systematic Review of Physical Activity and Sedentary Behavior Indicators in South-American Preschool Children

“…After the inclusion of two articles retrieved in manual searches, the descriptive summary consisted of a total of 13 original articles. [18][19][20][21][22][23][24][25][26][27][28][29][30] The study design determined that all included articles had a cross-sectional nature. In all, the summary gathered data from 11 different samples: five from Chile, five from Brazil, and one from Argentina.…”

“…In all, the summary gathered data from 11 different samples: five from Chile, five from Brazil, and one from Argentina. Studies by Lima et al 24 and Melo et al 26 used the same sample from Recife (Brazil), assessed in 2010, similarly to Vásquez and Salazar 28 and Vásquez et al, 29 who analyzed the same sample from Santiago (Chile). Five samples adopted randomized techniques for their composition, and the study by Roda et al 27 involved children from all child development centers in the city of Merlo (Argentina).…”

“…With respect to selection bias, only the evaluation of the articles by Vásquez resulted in a high risk of bias, as their sample was specifically composed of obese children. 28,29 Given the study design, the most common weaknesses were the lack of information about sample representativeness 18,21,[23][24][25][27][28][29] and the use of convenience samples. 23,25 Two articles did not report prior validation of the instrument used to evaluate physical activity 27 and sedentary behavior.…”

“…22 Three articles estimated the daily volume of moderate physical activity as 32, 70.1, and 71.3 minutes per day. 20,24,29 As to the volume of vigorous physical activity, two articles presented the following estimates: 15 and 21.7 minutes per day. 20,24 The mean daily time spent practicing moderate and vigorous physical activity was 92 and 97.1 minutes per day 18,23 (Table 3).…”

“…Considering accelerometer-based measurements, the summary identified the following prevalence rates: 12.7, 81.8, and 100% of preschool children who practice at least 60 minutes per day of moderate and vigorous physical activity 21,23,24 ( Table 3). In articles that used the questionnaires, we found prevalence rates of 34.7 and 58% of children who practice at least 60 minutes per day of outdoor 30 and moderate 27 physical activities, respectively.…”