Daily physical activity assessment in school children: Movimentiamoci Diary validation study

In a behavioural epidemiology perspective there are different dimensions for featuring and assessing physical activity (PA) profile: type, frequency, duration, intensity, correlates, outcomes. Scientific evidences on health and PA led to recommendations for children and adolescents. They should be at least moderately active for at least one hour a day with a wide range of possible activities: sports, physical education at school, free range play, active transport, dance, housework. In 2012 we carried out a validation study to assess criterion validity of an Italian Daily Physical Activity Diary (IDPAD), targeted at primary school children and originally created from overseas examples. 51 pupils (10-11 years old) of Abruzzo region (middle Italy) filled in IDPAD for four consecutive days, registering everything they do from 7.00 am to 12 pm in 68 intervals of 15 minutes. Using a coded system, they specified for each interval the kind of activity (e.g. sleeping, having lunch, getting dress, school lessons, sports, walking, homework, etc) and their perceived intensity (i.e. light, moderate, vigorous, very vigorous activity). We obtained METs-transformed data and the number of errors that occurred when reported intensity was too high or low compared with coded criteria. In three out of four days, a subsample of 18 children wore in a belt around their waist an electronic device, the Liferecorder – Plus accelerometer, collecting objective measures of PA intensity (METs) and motion (steps). For overall 54 days coupled data, self-report vs objective measures have been compared by means of pairwise Spearman’s Rho. Correlations between METs values for single intervals have been found not sufficient (rho ≤ 3.0) nor significant. However we found a significant sufficient correlation between the daily amount of bouts classified as LPA intense (Low PA, rho=0.42, p<0.01) and MVPA intense (Moderate to Vigorous PA, 0.47, p<0.001). MVPA level appears significantly higher in males than in females and it increases from week-days to week-end. At same time, sedentary activity (SA) increases in the week-end, interestingly confirming what recent scientific literature is showing: PA and SA have to be considered separated patterns of behaviour, with different mechanisms of influence on health outcomes. Our study demonstrated that the IDPAD has some limits due to subjective measures so it couldn’t be considered an exact instrument for assessing absolute energy expenditure in a quantitative analyses (e.g. causal relationship evaluation in epidemiological studies). However it is valid as raw quantitative assessment of daily child’s PA level. Nevertheless it makes subjects aware about what kind of activities they do more or less and how practically change their sedentary lifestyle. So, daily self-reporting PA by means of diary is a good instrument for health promoting interventions, from individual goal setting to impact assessment at school and population level.