A convenience sample of female participants (N ¼ 55, aged 13–14 years) was drawn from a mixedgender,
state and urban High School in the north of England. The school was socio-economically
privileged (Income Deprivation Affecting Children Index (IDACI) Rank: 30418/32482), followed
the statutory NCPE, and data collection was undertaken in the autumn term of the academic calendar
(DfCLG, 2008). The study received ethical approval from the University Ethics Committee and the
assent of all pupils; the consent of their parents and teachers was then obtained. Across lessons, 55
participants were observed; seven pupils took part in three observed lessons resulting in 21 observations,
39 in two observed lessons (78 observations) and 13 in one (13 observations), collectively producing
112 observations. An average of seven pupils per class wore accelerometers