Habitual physical activity levels in childhood and adolescence assessed with accelerometry

Abstract

Aim. The purposes of this study were: (1) to evaluate age and gender differences in PA of children and adolescents; (2) to find out if children and adolescents fulfill the PA recommendations. Methods. PA was assessed in 265 female and 238 male subjects, ranging from 6 to 18 years of age, with MTI actigraph model 7164, during 7 consecutive days, grouped in 4 age groups. The MTI actigraph data was reduced to bouts (30-, 20-, 10-, and 5-min) and minutes spent in moderate PA (MPA), vigorous PA (VPA), and very vigorous PA (VVPA). Results. The oldest boys and girls revealed a lower number of PA bouts. Significant gender differences were found in daily VPA, F(1, 492) = 37.67, p<0.001; and VVPA F(1, 494) = 24.11, p<0.001. Boys were more active than girls. Significant age group differences were also found in MPA, F(3, 494) = 87.40, p<0.001; VPA, F(3, 492) = 78.15, p<0.001; and VVPA, F(3, 454) = 54.89, p<0.001. In both genders MPA, VPA and VVPA decreased with age. Till the age of 14, children had means between 79.6±30.6 and 144.1±76.9 min*day-1 of PA. After this age there was a decrease to 44.1±19.9 min*day-1 in girls and to 56.3±31.9 min*day-1 in boys. Conclusions. Boys had more minutes a day of vigorous and very vigorous PA than girls. PA decreased with age. The children from 6 to 15 of this fulfilled the recommendations of 60 min*day-1 of moderate to vigorous PA.