Related Experiment Video
Updated: May 1, 2026

In Vivo Protocol of Controlled Subconcussive Head Impacts for the Validation of Field Study Data
Published on: April 18, 2019
Concurrent Agreement and Test-Retest Reliability of a Global-Positioning-System Device for Measuring Maximal
Lewys H Jones1,2, Cedric Leduc3,4, Kurt Greatorex1
1Academy Performance Department, Crystal Palace FC, London, United Kingdom.
Purpose:
Investigate the concurrent agreement and test-retest reliability of 10-Hz global-positioning-system (GPS) device against a criterion measure (47-Hz radar device) to assess maximal horizontal deceleration ability (maximum deceleration [DECMax], average deceleration [DECAve], time to stop, and distance to stop).
Methods:
Thirty-two male elite youth academy soccer players (age 18.1 [1.6] y, body mass 76.6 [7.9] kg) completed the acceleration-deceleration ability test with 16 completing a second test to assess test-retest reliability. Maximal horizontal deceleration ability was measured concurrently using GPSRaw (10-Hz data), GPSExport (STATSports software), and a radar device. Bland-Altman method and equivalence testing assessed concurrent agreement and intraclass correlations with coefficient of variation (%) was used to assess test-retest reliability.
Results:
Equivalence testing showed mean difference between the radar device and GPS-derived values of DECAve and DECMax were within equivalence bounds. GPSRaw and GPSExport derived values of DECMax showed good overall (intraclass correlations = .84-.86, coefficient of variation % = 4.50-5.48) test-retest reliability.
Conclusion:
Practitioners can consider using deceleration variables (DECAve and DECMax) obtained from GPS as a cost-effective, valid, and reliable alternative to radar technology to assess maximal horizontal deceleration ability in team-sport players.
Related Concept Videos
Electronic Distance Measuring Instruments
Introduction to Global Positioning System
Field Application of Global Positioning System
Types of Global Positioning System Surveys

