MOVI-OLE! [Open Learning Environments]

measured using accelerometers to record sitting/lying, standing, and walking time during classroom activities. Data are expressed as minutes per child during classroom time; higher values of sedentary time indicate greater inactivity.

measured in a randomly selected subsample using the Portable Ergonomic Observation Method. Observers will record and classify postures (sitting, standing, walking) during classroom time using real-time coding and/or video recordings. Minutes per child per posture category; higher sitting time indicates more sedentary behavior.

inhibitory control and attention will be measured using the Flanker Inhibitory Control and Attention Test. Children complete practice trials followed by a block of congruent and incongruent trials. Outcomes include reaction time, accuracy, and raw scores, with higher scores indicating better inhibitory control and attentional performance.

working memory will be assessed using the List Sorting Working Memory Test. Children are required to recall and sequence items presented visually and orally, with task difficulty increasing progressively. Outcomes include raw scores, with higher scores indicating better working memory performance.

cognitive flexibility will be assessed using the Dimensional Change Card Sort Test. Children classify stimuli based on color or shape, with blocks assessing both pre-switch and post-switch performance. Outcomes include reaction time, accuracy, and raw scores, with higher scores reflecting greater cognitive flexibility.

academic grades provided by the school in various subjects, comparing the year prior to the intervention and during the intervention years.

measured with questionnaire such as Revised Children's Anxiety and Depression Scale. This standardized questionnaire assesses a range of anxiety and depression symptoms in children. Responses are rated on a 4-point Likert scale, and scores are converted to age- and sex-normed T-scores. T-scores ≥65 indicate borderline clinical levels, and scores ≥70 indicate clinically significant symptoms.

measured with questionnaire KIDSCREEN. This standardized instrument evaluates physical, psychological, and social dimensions of well-being in children and adolescents. Items are rated on 5-point Likert scales, and scores are transformed into T-scores. Higher T-scores indicate better HRQoL.

student engagement (based on the Achievement Beliefs Scale for Children). This self-report instrument evaluates motivational and cognitive components of academic engagement in children, such as effort, persistence, and beliefs about success. Items are rated on Likert-type scales, with higher scores indicating greater levels of engagement.

teacher personal efficacy (Utrecht Work Engagement Scale; UWES). This self-report questionnaire measures work engagement through three dimensions: vigor, dedication, and absorption. Items are rated on a 7-point Likert scale. Higher scores indicate greater work engagement and perceived efficacy.

estimation of oxigen (O2) consumption during lessons in traditional seated, dynamically seated and standing desks will be assessed in a a randomly selected subsample. It wil be estimated the O2/hour consumption using a K5 COSMED (Oxycon Mobile system; CareFusion) wireless portable metabolic analyzer.

weight will be assessed twice using a calibrated digital scale with children barefoot and in lightweight clothing.

height will be measured twice with a stadiometer, with children standing upright, barefoot, and with the sagittal midline aligned to the wall.

BMI will be calculated as weight divided by height squared (kg/m2).

body compositipon will be assessed twice using the bioimpedance analysis system under standardized conditions (morning, fasting, post-void, after 15 minutes rest, barefoot, with controlled temperature and humidity).

blood pressure will be measured using an automated device (OMRON-M5-I). Systolic and diastolic blood pressure will be assessed twice, with a 5-minute interval between measurements. Children will be seated in a quiet environment, with the right arm semi-flexed at heart level.

objectively measured with accelerometers worn for 7 consecutive days, including sleep hours in a subsample.

assessed using the 20-meter shuttle run test, which estimates aerobic capacity. Number of completed stages or laps; higher values indicate better fitness.

measured through handgrip strength using a calibrated dynamometer and standing long jump for lower body strength. Handgrip: Kilograms (kg). Horizontal jump: Centimeters (cm).

measured using the 4×10 meter shuttle run test, assessing coordination, speed, and agility. Seconds (s); lower scores indicate better performance.

assessed using the Standardized Nordic Musculoskeletal Questionnaire (NMQ), which includes questions about frequency and intensity of neck and back pain over the past 12 months and the past 7 days.Presence of pain (yes/no), and categorical frequency scores (e.g., never, occasionally, often, always); higher values indicate more frequent pain.

qualitative study will explore the perceptions of teachers, students, and school leadership regarding the facilitators and barriers to implementing the MOVI-OLE! classroom intervention. Data will be collected using qualitative research techniques (e.g., semi-structured interviews, focus groups) and analyzed through thematic analysis. Thematic categories and frequency of themes across stakeholder groups.

collected from parent questionnaires and/or health records. Includes birth weight (kg), gestational age (weeks), breastfeeding status (yes/no), and maternal weight gain during pregnancy (kg). Variable-specific (e.g., kg for weight, weeks for gestational age); categorical for breastfeeding (yes/no).

self-reported parental weight and height will be used to calculate Body Mass Index (BMI) for both parents. Weight: kilograms (kg); Height: meters (m); BMI: kg/m2.

assessed using parent-reported questionnaires on children's sedentary recreational activities and screen time outside school hours. Minutes per day; higher values indicate more sedentary time.

dietary intake and food patterns assessed using the Children's Eating Habits Questionnaire (CEHQ). Scale-specific scores; higher values may indicate healthier or unhealthier habits depending on the subscale.