Validation and extension of a simple questionnaire to assess physical activity in pre-school children

Objective: To (i) validate a recently proposed questionnaire tool for the simple assessment of physical activity (PA) in pre-school children by comparison with accelerometry and heart-rate recordings; and (ii) extend the tool by adding more questions to improve validity and to refine the classification from two to three categories (PA low, medium, high). Setting: Baseline data of an intervention evaluation study. Subjects: Pre-school children. Design: Children were categorized as either physically active or non-active, based on their parents' answers to the five-item questionnaire. Activity and heart rate were recorded for 6 d (Actiheart device; CamNtech, Cambridge, UK). Nightly sleeping periods were removed and mean accelerometry counts (MACT), time spent in moderate-to-vigorous intensity physical activity (MVPA) and time spent in sedentary behaviour (SB) were computed. In a second step, additional questions that improved validity were added, resulting in an extended seven-item questionnaire. Results: For 748 (90.4%) of the participating children aged 2.3-6.7 years, the questionnaires were filled out sufficiently for classification. Children classified as physically active showed 9.6% higher MACT (P<0.0003), spent more time in MVPA and insignificantly less time in SB. Using the extended questionnaire, children with PA classified as medium (reference: low) showed 11.0% more MACT, spent 11.8% more time in MVPA and 4.8% less time in SB. Children with PA classified as high showed 16.9% more MACT, spent 20.2% more time in MVPA and 7.2% less time in SB. Conclusions: With validated PA questionnaires for pre-school children lacking, the proposed questionnaire might be a reasonable option to include for PA assessment in epidemiological studies where more elaborate measurements are unavailable.