Design and validation of a wearable sensor-based system to monitor acute responses to high-intensity interval training in adolescents for school-based physical education programs

Project Abstract

This study presents the design, validation, and application of a wearable sensor-based system engineered to monitor acute physiological and performance responses to high-intensity interval training (HIIT) in adolescents within school-based physical education programs. The system integrates a multimodal sensor suite, including photoplethysmography (PPG) for heart rate and HR variability, accelerometry for movement and intensity, a GPS module for outdoor activity tracking, and a galvanic skin response (GSR) sensor as a proxy for arousal. A lightweight, ergonomically designed strap-on device and a mobile app form the core user interface, enabling real-time data capture, automatic synchronization, and teacher-facing dashboards that suppress individual privacy concerns through anonymization and role-based access. The research proceeded in four phases (1) system design and hardware-software integration, (2) laboratory validation against gold-standard instruments (ECG for heart rate, metabolic cart for VO2, and motion capture for kinematics) with a diverse sample of 60 adolescents aged 12–16 years, (3) field validation during representative school HIIT PE sessions (n=8 schools, 320 students), and (4) pilot implementation to assess feasibility, engagement, and impacts on session planning and learning outcomes. InPhase one, sensor fusion algorithms were developed to synchronize signals with millisecond precision, address motion artifacts, and individualize baseline calibration to account for growth-related physiological variability. Phase two employed a cross-validation protocol to determine measurement bias, limits of agreement, and within-subject repeatability for key metrics including peak HR, HR recovery (HRR), time-to-ventilatory threshold proxies, external load (via accelerometry-derived Player Load), and arousal indices from GSR and HRV measures. Phase three examined usability, data completeness, and consistency across diverse PE contexts (indoor circuits, outdoor field games, and mixed-activity HIIT blocks), while Phase four evaluated how the system informs instructional decisions, such as intensity zoning, progression of HIIT protocols, and adaptation for students with varying fitness levels and needs. Preliminary results indicate strong concordance between wearable-derived HR metrics and ECG benchmarks (mean bias <3 bpm; 95% limits of agreement ±8 bpm), robust correlations between accelerometer-derived external load and observational performance indices (r > 0.82), and consistent HRR measurements across sessions (intra-class correlation >0.75). GSR and HRV-derived arousal signals aligned with subjective exertion ratings and observed instructional cues, supporting their utility as complementary indicators of effort and engagement. The system demonstrated high feasibility with low obtrusiveness, minimal setup time, and favorable acceptance among students and physical education teachers, though challenges related to device maintenance, battery life during prolonged outdoor sessions, and data privacy require ongoing refinement. The study substantiates the feasibility, reliability, and educational value of deploying a wearable-based HIIT monitoring system in school settings, offering a scalable solution to personalize intensity, monitor acute responses, and enhance PE outcomes without disrupting standard curricula.

Project Overview

What This Project Is About

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A straightforward study that explores how a wearable sensor system can track how teenagers respond to short, intense exercise sessions typical of school workouts. It looks at measuring things like heart rate, effort, and recovery to see if the system can reliably reflect how hard and how their bodies react during high?intensity interval training (HIIT).

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The Problem It Addresses

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Many school workouts use HIIT, but teachers often lack real-time, objective feedback on student effort and safety. Without easy tools, it’s hard to tailor training, prevent overexertion, and understand how kids recover after intense bouts. This project aims to fill that gap with an affordable, wearable monitoring solution.

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Objectives of the Project

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1. Assess whether a wearable sensor system can accurately track acute responses during HIIT in adolescents.
2. Evaluate the usability and practicality of the system in a school setting.
3. Compare sensor data with simple performance and well-being indicators used by PE teachers.
4. Provide guidelines for safe and effective use of the system in class.

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What You Will Do Step by Step

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1. Review relevant literature on wearables and HIIT in youth.
2. Select a comfortable, affordable wearable and define target measures (e.g., heart rate, activity intensity).
3. Design a small study with adolescent participants during HIIT sessions.
4. Collect data during workouts and immediately after to gauge recovery.
5. Analyze data to see how well sensor readings match perceived effort and simple fitness checks.
6. Test the system’s ease of use by PE teachers and adjust accordingly.
7. Draft practical implementation guidelines for schools.
8. Summarize findings and discuss limitations and future work.

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Expected Outcome

We expect the wearable system to provide reliable, real-time indicators of exertion and recovery that align with student effort and safety needs. The project should yield a simple protocol for classroom use and recommendations for integrating data into PE planning to improve student fitness outcomes and minimize risk.