Investigating the relationships between elements of a revised theory of planned behaviour and objectively measured physical activity behaviours [HAPPY Study]

Objectives: This study examined the relationships between constructs of a revised Theory of Planned Behaviour (TPB) and moderate to vigorous physical activity (MVPA) levels in 10–14 year-old schoolchildren. Methods: Ninety-one schoolchildren (boys n = 34; girls n = 57) completed a health perceptions questionnaire measuring the constructs of a revised TPB which included attitude, subjective norms, behaviour-specific self-efficacy (BSSE) and intentions to be active. Physical activity behaviours were recorded objectively over seven consecutive days using RT3® triaxial accelerometers. Multiple regressions were employed for each gender to explore the relationships of each of the revised TPB constructs with: 1. intentions to be active and 2. weekday and weekend MVPA. Results: For boys, subjective norms were correlated with intention (r = 0.653, p < 0.001). For girls, attitude (r = −0.570), subjective norms (r = 0.433) and BSSE (r = 0.517) correlated with intention (p < 0.001). No significant relationships were found for either gender between the revised TPB constructs and weekday or weekend MVPA. Conclusions: In this study 10–14 year old schoolchildren have developed cognitions which support intentions to be active but these intentions are not necessarily transferred into actual physical activity.