Affordable open-source system for measuring sprint-test times

Abstract

Introduction: Ultrasonic sensors integrated with open-source microcontrollers may represent a promising lowcost alternative for sprint assessment. However, evidence regarding their validity and reliability remains limited. Objective: The objective of this methodological study was to develop and valuate the validity and test-retest reliability of a low-cost sprint-timing system based on ultrasonic sensors and an open-source electronic prototyping platform incorporating open hardware and software. Methods: Ten physically active men (22.0 ± 2.6 years) participated in the study. Each participant completed two experimental sessions, with three maximal flying 30-m sprints performed per session. To assess concurrent validity, sprint times recorded by the prototype were compared with measurements obtained through video analysis using Kinovea software. The developed system consisted of two sensors. Each sensor included an HC-SR04 ultrasonic sensor to detect the runner's passage, an nRF24L01 wireless communication module to enable communication between the sensors, an Arduino Uno microcontroller responsible for executing commands programmed in C++, and, for Sensor 2, a 9-V battery to power the system. Test-retest reliability was evaluated by comparing the measurements recorded across the two experimental sessions. Results: The results demonstrated excellent agreement (ICC = 0.96), associated with low measurement errors. Bland–Altman analysis showed that most observations fell within the limits of agreement (bias ± 1.96 SD), and the bias was close to zero (0.08 s). In the test–retest analysis, reliability was high (ICC = 0.81), with low typical error. Bland–Altman analysis showed a small bias between the test and retest measurements (0.08 s). Conclusion: It is concluded that the developed system represents an accessible alternative for real-time sprint time assessment, demonstrating satisfactory validity and reliability for 30-m sprint tests.