The Effects of an In-school Physical Activity Intervention on Adolescents' Brain Structure and Function ('Fit to Study' Brain Imaging Sub-study)

Physical activity has shown beneficial effects for cognitive and brain health. In particular, studies have shown that physical activity has the potential to increase the volume of the anterior portion of the hippocampus, a brain structure involved in learning and memory. The Fit to Study - Brain imaging sub-study is being conducted to understand better the effects of a physical activity intervention delivered during school PE lessons on anterior hippocampal volume, as well as cognition, mental health, and brain organisation.

The Fit to Study main trial aims to test the effect of a school-based physical activity intervention on academic performance (as well as cognition and physical measures) across Year 8 pupils in 100 secondary schools. A full description of the Fit to study main trail, including its outcome measures, has been provided as part of its registration at ClinicalTrials.gov (NCT03286725).

The Fit to Study - Brain imaging sub-study will target a sub-sample of participants of the large-scale trial, in order to test pre to post intervention changes in anterior hippocampal volume, as well as cognitive performance, mental health and brain organisation. The assessments will take place pre-intervention, immediately post-intervention and 12-months post-intervention, and will comprise structural and functional magnetic resonance imaging (MRI) scans.

Fit to Study main trial participants are considered eligible for brain imaging sub-study. The brain imaging sub-study consists of two sub-samples, recruited at different times during the trial:

1. The first cohort of 60 participants completed assessments pre-intervention, will complete identical assessments post-intervention to investigate pre-to-post intervention changes, and will be invited to take part in follow-up assessments.
2. A second cohort of ~50 participants will be recruited for post-intervention assessments that are similar, but not identical, to the assessments of the first group, as well as 1-year follow-up assessments. This cohort will enable cross-sectional analysis of between-group (intervention-control) differences in a larger sample.