Optimising sprint performance: concurrent validity and reliability of 25hz gnss units for speed profiling

Sprint performance profiling is crucial for understanding an athlete’s capabilities and identifying potential areas for improvement. While traditional gold standard systems provide valid and reliable measurements, they are often costly, laboratory-based, or impractical for field-based settings. New GNSS units (25Hz) with higher sampling rates may address some of these limitations. The purpose of the project was to evaluate the concurrent validity and inter-unit reliability of 25Hz GNSS units by examining their agreement with laser devices for velocity measurements and timing gates for interval times. Validity was assessed during a track and field training session. 30 participants performed between 3 and 6 sprints over 40m whilst being assessed simultaneously through all systems. Inter-unit reliability was assessed on a closed athletics track by placing 3 GNSS units on a motor vehicle and completing 60 accelerations from 0-60m. Low mean bias (<1%) and typical error less than <2% for all measurements demonstrate excellent agreement between GNSS and criterion devices. The units demonstrated good reliability for the 0-10m interval (ICC = 0.86), excellent reliability for all remaining 10m intervals to 60m (ICC = 0.91-0.99), full times 0-60m (ICC = 0.97) and maximal sprint velocity (ICC = 1.0). These GNSS units offer a more efficient and practical alternative to traditional measurement devices. For coaches, this technology offers a scalable method to concurrently assess the sprint performances of multiple athletes during training and competitions, enabling evidence-based decisions to guide athletic development.