Inter-System Agreement and Reliability of a Gnss-Rtk and Dual-Imu Wearable System for Soccer Performance Monitoring
Rostami¹ S, Yazdchi² MR, Rajaeian³ B, Shirazi⁴ A, Hashemipoor⁴ MA, Kamali I. · Research Square · 2026
Abstract
Purpose: This study evaluated the inter-system agreement and interunit reliability of a GNSS real-time kinematic (GNSS-RTK) and dual-inertial measurement unit (IMU) wearable system during soccer-specific activities using a commercially available 10-Hz GNSS device as a field-based comparison system.
Methods: Thirty trained male team-sport athletes completed sport-specific drills, simulated match activities, and competitive match-play scenarios while simultaneously wearing the GNSS-RTK/dual-IMU system and a 10-Hz GNSS device. External-load variables included total distance, peak speed, and distance covered within predefined speed zones. Inter-system agreement was assessed using paired-samples t-tests, Pearson correlation coefficients, and Bland-Altman analysis. Interunit reliability was evaluated using intraclass correlation coefficients (ICC) and percentage typical error of measurement (%TEM).
Results: No significant differences were observed between systems for any external-load variable (p > 0.05). Strong correlations were identified for total distance (r = 0.89), peak speed (r = 0.84), and high-speed running distance (r = 0.81), whereas agreement was substantially lower for very high-speed running (VHSR) distance (r = 0.65). Bland-Altman analysis demonstrated small mean biases for total distance (− 6 m), peak speed (+ 0.08 km·h⁻¹), and low-speed running distance (− 8 m). Interunit reliability of the GNSS-RTK system was good to excellent across most variables (ICC = 0.80–0.96). The lowest measurement error was observed for low-speed and time-based variables, whereas VHSR-related metrics demonstrated considerably greater variability (%TEM = 11.2–13.2%).
Conclusions: The GNSS-RTK and dual-IMU wearable system demonstrated acceptable inter-system agreement and good-to-excellent interunit reliability for several key external-load variables in soccer. Agreement was strongest for cumulative locomotor metrics such as total distance and peak speed, whereas VHSR metrics exhibited lower agreement and greater measurement variability. These
Findings: support the practical application of GNSS-RTK technology for monitoring external load in soccer, provided that high-intensity running metrics are interpreted with appropriate caution.