Assessment of Intensity,
Prevalence and Duration
of Everyday Activities in
Swiss School Children: A
Cross-Sectional Analysis of
Accelerometer and Diary Data
Bettina Bringolf-Isler, Leticia Grize, Urs Mäder, Nicole Ruch,
Felix H. Sennhauser and Charlotte Braun-Fahrländer
Appropriately measuring habitual physical activity (PA) in children is a ma-
jor challenge. Questionnaires and accelerometers are the most widely used
instruments but both have well-known limitations. e aims of this study
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were to determine activity type/mode and to quantify intensity and duration
of children’s everyday PA by combining information of a time activity diary
with accelerometer measurements and to assess dierences by gender and age.
School children (n = 189) aged 6/7 years, 9/10 years and 13/14 years wore
accelerometers during one week in winter 2004 and one in summer 2005.
Simultaneously, they completed a newly developed time-activity diary during
4 days per week recording dierent activities performed during each 15 min
interval. For each specic activity, the mean intensity (accelerometer counts/
min), mean duration per day (min/d) and proportion of involved children
were calculated using linear regression models.
For the full range of activities, boys accumulated more mean counts/min
than girls. Adolescents spent more time in high intensity sports activities than
younger children (p < 0.001) but this increase was compensated by a reduc-
tion in time spent playing vigorously (p = 0.04). In addition, adolescents
spent signicantly more time in sedentary activities (p < 0.001) and accu-
mulated less counts/min during these activities than younger children (p =
0.007). Among moderate to vigorous activities, children spent most time with
vigorous play (43 min/day) and active transportation (56 min/day).
e combination of accelerometers and time activity diaries provides insight
into age and gender related dierences in PA. is information is warranted
to eciently guide and evaluate PA promotion.
Childhood overweight and obesity are increasing in many countries including
Switzerland  and there is growing concern that decreasing levels of physical
activity (PA) may contribute to this development. Still, appropriately measuring
PA in children is a major challenge. Questionnaires and accelerometer measure-
ments are the most widely used instruments [2,3]. Self- or proxy reports provide
information about mode/type and duration of PA but show limited validity in
assessing PA levels and are susceptible to reporting bias by social desirability .
On the other hand, accelerometer measurements provide valid overall estimates of
intensity of PA [5,6]. Nevertheless, they neither determine which activities con-
tribute most or least to PA in children nor the variation in the type and duration
of habitual activities over time. Yet, this information is of great importance for