60 minutes of daily physical activity (see intervention)

The "Active school" study was a 10-month randomized controlled trial.The weekly interventions were 2×45 minutes physically active academic lessons, 5×10 minutes physically active breaks, and 5×10 minutes physically active homework.

Response inhibition was measured by Stroop Golden color-word test. Participants were naming the printed color of color words while suppressing the reading of the words. The measure was the number of words read in 45 Seconds.

Working memory was tested by the Wechsler Adult Intelligence Scale (WAIS)-IV-test, a forward and backward digit span, a test that measures working memory function. The measure was the length of the correct series of numbers repeated by the participant.

was included

Cognitive flexibility was tested by two tests. First the participants were asked to list all the animals they could think of in 60 seconds as fast as they could.The number of animals was the score. Second, participants performed the Trail Making test. This involves drawing a line connecting consecutive numbers from 1 to 25 as fast as possible. Then participants were drawing a similar line, connecting alternating numbers and letters in sequence, example: 1-A-2-B. Time to complete each "trail" was recorded.

Aerobic fitness was assessed by a 10-minute interval running test. The children ran back and forth between two lines placed 20 m apart, touching the ground behind the line with their hand every time they reversed direction.

After 15 seconds, a teacher signaled stop and the children rested for 15 seconds before they once more ran for 15 seconds. This procedure lasted 10 minutes, and the running distance was the outcome measure.

Physical activity was measured using accelerometry (ActiGraph GT1M/GT3X/GT3X+, LLC, Pensacola, Florida, USA).

The children were asked to wear the accelerometer on the right hip for seven consecutive days, removing it only during water-based activities (e.g., swimming) and while sleeping. Data were considered valid if a child had at least two days with a wear time of ≥480 min/day accumulated between 06:00 and 24:00.

Self-regulation was measured by the Child Behavior Rating Scale (CBRS). This is a teacher rating based on the Bronson Social Task and Skill Profile, designed to assess children's classroom goal-oriented behaviors and strategies used to regulate behavior in academic and social situations. The teacher report consisted of 10 items used to assess children's self-regulation in the classroom.