6]), so provision was made for the elimination of data recorded on days when conditions were especially adverse (e.g., intense rain or cold). However, no data were required to be removed on these grounds.

In addition to calculating the average number of steps taken by participants, the analysis also grouped results according to the index categories established by [@B103]: "sedentary" (\<5,000 steps per day), "low active" (5,000--7,499 steps), "somewhat active" (7,500--9,999), "active" (10,000--12,499), and "highly active" (\>12,500). In view of the low number of participants in the final two ranges, these scores were classed together as "active or highly active."

### Number of Physical Activities Carried Out {#S2.SS2.SSS4}

Participants were asked to state the different physical activities performed over the course of the week. Spaces were provided in the questionnaire for two unstructured activities and two organized activities on weekdays, and two unstructured activities and two organized activities on the weekend. The range of values for each type of activity was 0--4, with a maximum total value of 8 as the sum of the week's activities.

### Level of Autonomy in Physical Activities Carried Out {#S2.SS2.SSS5}

Level of autonomy was calculated based on the number of activities carried out. Participants who practiced just one activity were classified as "unstructured" or "organized" depending on the type of activity performed. Where the difference between activity types was more than 1, participants were classified according to the higher scoring activity. Where the difference between activity types was less than or equal to 1, participants were classified as "mixed" (both unstructured and organized).

Procedure {#S2.SS3}
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The principals of the schools selected for the study were contacted and informed of the objectives and procedure of the study. Once the schools' agreement had been obtained, permission for students to participate in the study was requested from their families using an informed conse