The main aim of the MENTALFIT project is to test the effectiveness of physically active teaching methodologies to reduce mental fatigue and optimize cognitive, emotional, and motivational processes in secondary school students. Specifically, the study aims to examine differences depending on the type of physically active strategy implemented (physically active learning, active breaks, and active recesses) on students' mental fatigue, cognitive function, group dynamics, and motivational processes. Furthermore, the project aims to compare whether learning and academic performance are similar in traditional classes versus classes employing a physically active teaching methodology. Finally, a secondary objective of the project is to create and validate new instruments to assess the different psychobiological and educational processes included in this project.
Background and Rationale Mental Fatigue (MF) is a dynamic psychobiological state induced by prolonged cognitive and emotional demands. In educational contexts, particularly in secondary education, it manifests as a cascading deterioration affecting attention, executive function, emotional regulation, and learning capacity. Despite its relevance, MF remains understudied in adolescents. Secondary school students face substantial sedentary demands, spending an average of 78% of the school day in sedentary activities. These schedules, characterized by extended periods of continuous instruction with minimal breaks, create conditions conducive to MF development. The MENTALFIT project aims to address this by reintegrating movement into school routines to counteract MF and its associated cognitive decrements. Study Design and Methodology This quasi-experimental study (Study 3 of the MENTALFIT overarching protocol) employs a multifactorial design to evaluate the differential effectiveness of three physical activity (PA) interventions. The study is conducted over a full academic year (2024-2025) across several secondary schools in Extremadura, Spain. The sample comprises adolescents in their 3rd and 4th year of secondary education (aged 13-17). The sample is divided into four groups: one control group ("business as usual") and three experimental groups. To compare the effectiveness of different approaches, each experimental center implements three distinct physically active strategies in a counterbalanced rotation across the three trimesters. This ensures that each experimental group receives every type of intervention while controlling for order effects. Intervention Components The multicomponent intervention includes: Physically Active Lessons (PAL): Integrating motor activities with curriculum content. Active Breaks (AB): Short bouts of physical activity delivered between or during lessons. Active Recess (AR): Structured opportunities for physical activity during break times. Data Collection Data are collected at six measurement points throughout the academic year (at the beginning and end of each trimester). Assessments include standardized self-report measures evaluating mental fatigue perception, academic burnout, school engagement, academic motivation, and well-being. Furthermore, objective measures are collected, including academic grades (GPA), computerised neuropsychological batteries (Stroop, PASAT, PVT-B), continuous heart rate and physical activity monitoring via Fitbit devices, and brain activity via Electroencephalography (EEG) in a selected subsample to capture objective neural correlates of mental fatigue.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
434
AB are implemented three times per week on days without physical education classes, providing a total of six active break sessions weekly (two per day on intervention days). Each session consists of 5 minutes of physical activity scheduled after the second and fifth academic periods to interrupt prolonged sedentary behaviour. Delivered over 9 weeks per trimester. A specialised facilitator provides direct support during all intervention sessions to coordinate the timing and implementation of activities.
PAL integrates physical movement into academic instruction. Two 55-minute lessons per week are dedicated to integrating motor activities with curriculum content. The intervention is coordinated by a specialised facilitator who co-designs the sessions with subject-matter teachers to maintain academic rigor while promoting physical engagement. Delivered over 9 weeks per trimester.
AR provides structured opportunities for physical activity during school breaks. Every day of the week, two activities are offered during recess: one involving moderate physical activity and another involving more vigorous or intense activity (alternative games). The intervention modifies playground spaces and provides diverse sports equipment to encourage movement. Delivered over 9 weeks per trimester. A specialised facilitator provides direct support during all intervention sessions to coordinate the implementation of the activities.
University of Extremadura
Cáceres, Spain
Subjective Mental Fatigue (VAS-F)
Assessed through the Visual Analogue Scale for Fatigue (VAS-F; Smith et al., 2019). It is a 100mm single-item measure of overall fatigue intensity. Scores range from 0 to 100, where higher scores indicate a higher perception of mental fatigue.
Time frame: Assessed at 6 time points across the academic year: beginning and end of trimesters 1, 2, and 3 (Baseline up to 9 months).
Multidimensional Mental Fatigue (PedsQL MFS)
Pediatric Quality of Life Inventory Multidimensional Fatigue Scale (Varni \& Limbers, 2008), 9-item Spanish version. It measures general, sleep/rest, and cognitive fatigue. A composite score is calculated as the mean across items. Higher scores indicate greater problems with fatigue.
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Objective Neurophysiological Mental Fatigue (Brain Activity)
Assessed via EEG recordings using Emotiv EPOC X headsets. Recordings are taken during resting-state and cognitive tasks (Stroop, PASAT, PVT-B) to characterize neural correlates (theta, alpha, and beta frequency bands) of cognitive performance under conditions of mental fatigue.
Time frame: Assessed at 6 time points across the academic year in a subsample of 160 students (Baseline up to 9 months).
Objective Cardiovascular Indicators (Heart Rate and HRV)
Fitbit Charge 6 devices worn continuously for one week at each measurement point to provide 24-hour assessments of heart rate and heart rate variability (HRV) as indicators of fatigue and autonomic nervous system state.
Time frame: Assessed at 6 time points across the academic year in a subsample of 160 students (Baseline up to 9 months).
Objective Physical Activity and Sleep Patterns
Fitbit Charge 6 devices worn continuously for one week providing assessments of sleep metrics (duration, efficiency) and PA patterns (steps, intensity minutes, sedentary time).
Time frame: Assessed at 6 time points across the academic year in a subsample of 160 students (Baseline up to 9 months).
Self-reported Physical Activity Frequency
Assessed via a single-item question asking participants about their weekly physical activity volume (including PE classes and outside school). Rated on a 5-point scale ranging from "None" to "More than 7 hours".
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Self-reported Sleep Duration
Assessed via a single-item question asking about the average hours of sleep per day (including night sleep and naps). Responses range from "Less than 3 hours" to "More than 10 hours".
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Self-reported Screen Time
Assessed separately for weekdays and weekends via a single question about hours spent on screens (TV, mobile, video games, social media). Rated on a 7-point scale ranging from "0 minutes" to "5 hours or more".
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Cognitive Performance (Neuropsychological Battery)
A computerized battery assessing cognitive inhibition, selective attention, working memory, and sustained attention using three specific tasks: the Stroop task, the Paced Auditory Serial Addition Test (PASAT), and the Psychomotor Vigilance Task-Brief (PVT-B).
Time frame: Assessed at 6 time points across the academic year in a subsample of 160 students (Baseline up to 9 months).
Perceived Executive Functioning (WEBEX)
Perceived difficulties and efficacy in everyday executive functioning evaluated using the WEBEX Scale (Morea \& Calvete, 2020).
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Academic Performance (GPA)
Grade point average (GPA) obtained from students' official academic records across all compulsory subjects.
Time frame: Assessed at 3 time points across the academic year (Baseline up to 9 months).
Academic Burnout (MBI-SS)
Maslach Burnout Inventory-Student Survey (12 items). Comprises three dimensions: emotional exhaustion, cynicism, and academic efficacy. A composite burnout score is calculated.
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
School Engagement (UWES-S)
Assessed using 3 items from the Utrecht Work Engagement Scale for Students measuring vigor, dedication, and absorption. Items are rated on a 7-point scale (0-6).
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Perceived Mental Load
Assessed using an adapted 3-item scale (Díaz-García et al., 2018) measuring perceived physical, cognitive, and emotional demands of the school week. Rated on an 11-point scale (0-10).
Time frame: Assessed at 6 time points across the academic year (Baseline up to 9 months).
Motivation towards Exercise (BREQ-3)
Assessed using 6 items representing the six regulation types of the Behavioral Regulation in Exercise Questionnaire-3. Rated on a 5-point scale (0-4).
Time frame: Assessed at 3 time points: beginning, middle, and end of the academic year (Months 0, 4.5, and 9).
Classroom Social Dynamics (CCQ-SF)
Class Cohesion Questionnaire Short-Form (Leo et al., 2023) measuring task and social cohesion (6 items total).
Time frame: Assessed at 3 time points: at the end of trimesters 1, 2, and 3 (Months 3, 6, and 9).
Subjective Happiness (SHS)
Assessed using the Spanish adaptation of the Subjective Happiness Scale (Extremera \& Fernández-Berrocal, 2014).
Time frame: Assessed at 2 time points: beginning and end of the academic year (Month 0 and Month 9).
Adherence to the Mediterranean Diet (KIDMED 2.0)
Assessed using the KIDMED 2.0 questionnaire (Spanish version; López-Gajardo et al., 2022) to evaluate adherence to the Mediterranean diet. Higher scores indicate better adherence to healthy dietary habits.
Time frame: Assessed at measurement point 5 (approximately Month 7.5 of the academic year).
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