Table 1 Action 3:30 SPIRIT diagram displaying study recruitment and measures schedule

Timepoint

Opt-out

T0

Randomization

Intervention

T1

 Opt-out consent

X

 Opt-out survey (12 schools)

X

 Opt-out accelerometer (4 schools)

X

X

 Informed parental consent

X

 Baseline measures

X

 Randomization into study arm

X

 TA training (intervention schools)

X

 Extracurricular physical activity intervention (6 schools)

X

 Normal treatment (6 schools)

X

 Percentage opt-out

X

X

 Self-reported physical activity

X

 Percentage opt-in (total, by sex)

X

 Participant characteristics

X

X

 Self-reported psychosocial questionnaires

X

X

 Economic evaluation

X

X

 Mean daily moderate-to-vigorous physical activity

X

X

 Process evaluation

X

X