Objectively Measured Free Living Physical Activity - a Socio-Cognitive Theory Based Intervention to Increase Physical Activity Levels in Scottish Adolescent Children

  • Paul Robert Walker McCrorie

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


Physical inactivity is the 4th leading risk factor for global mortality. In Britain, three in ten children (2-15yrs) are overweight or obese, and type 2 diabetes is becoming more prevalent. Physical activity (PA) is an important moderator for health and PA guidelines have been developed to optimise the benefits of PA.

There were two main aims of this thesis: The first was to investigate the influence of season on PA levels in adolescents (ll-13yrs, 1st year secondary schooling, Ayrshire, Scotland). The second was to design and implement an intervention to increase steps and moderate to vigorous PA (MVPA).

The seasonal variation study (n = 33) examined PA using objective measurement (activPAL™). Results supported the hypotheses that PA is higher in the summer (13,070 steps/d) compared to winter (10,980 steps/d). The greatest variation was evident in the evening (16:00-22:00), and provided the focus of the intervention. The school-based intervention (n = 32) was embedded within an 8-week, curriculum based health project, with 3-weeks of PA content underpinned by social cognitive theory (SCT). Intervention involved standard (increasing knowledge of PA, self-efficacy, intentions and outcome expectations) or enhanced (additional self-regulatory skills; action and coping planning) groups, with outcomes measured at baseline, postintervention and 6-month follow-up. PA outcomes included steps and volume of MVPA. Socio-cognitive outcomes included self-efficacy, intentions, action and situation outcome expectations (AOE and SOE), and planning (action and coping). Whilst there were intervention effects in some socio-cognitive/planning measures (action planning at post, and SOE at 6-month) there were no significant post or 6- month group effects across any PA measure, including the after school and evening periods - a central focus of the intervention.

The development of the intervention demonstrated the feasibility of theory-based PA promotion in a cost effective manner. Whilst no significant PA effects were found, this work can be used to inform further, school-based, PA intervention studies.
Date of Award2012
Original languageEnglish
Awarding Institution
  • Glasgow Caledonian University
SupervisorBen Stansfield (Supervisor) & Elaine Duncan (Supervisor)

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