Formative Evaluation of The HERizon Project

This mixed methods study was the feasibility phase of a broader intervention of research (The HERizon Project) that aims to develop a theory-based physical activity intervention targeting adolescent girls in the UK and Ireland. The design was a two-arm randomised controlled trial, comprising of (i) the HERizon six week remote intervention arm and (ii) a wait-list control arm. Block randomisation with country-level stratification was used to allocate the participants on entry. The primary outcome of the study was change in moderate to vigorous physical activity levels. Secondary outcomes included cardiorespiratory fitness, muscular strength and endurance, exercise motivation, perceived competence, self-esteem and body appreciation. Assessments were conducted pre-intervention (April/May, 2020) and repeated immediately post-intervention (June/July, 2020). As the study ran during the COVID-19 pandemic, all participants began the intervention in full national lockdowns, with all local schools and amenities being closed. Restriction began to be lifted in the last week of June in Ireland and in the first week of July in the UK, with some local amenities opening and small outside group gathering being permitted. Due to the nature of the study, participants and project deliverers could not be blinded to the assigned intervention.