The validity and reliability of a 5-hz GPS device for quantifying athletes’ sprints and movement demands specific to team sports

Abstract

GPS systems are commonly used to analysis football performance during either trainings or matches. While many studies have investigated the validity and reliability of these devices, there is a lack of objective procedures regarding synchronization with gold standards such as real distance or timing gates. The objective of this study was to study the validity and reliability of a 5Hz GPS system (WIMU) during 10m and 30m sprints and during team sports specific movements and the reliability during very high speeds (> 30 km/h). The Total Distance (TD) BIAS for Circuit A, 10m sprint and 30m sprint were -2.73 ± 1.64 m (p < 0.001), -0.80 ± 0.58 m (p<0.001) and 0.42 ± 2.50 m (p=0.515) respectively. Average ICC for GPS speed point-to-point were 0.976 ± 0.012 and 0.991 0.003 for Circuit B and Motorized Sprints, respectively. The average BIAS compared with each unit mean laps (intra-unit reliability) results for TD, Peak-Speed and Avg-Speed were 0.00 ± 1.68, 0.00 ± 1.73 and 0.00 ± 0.33 for Circuit A, 0.00 ± 0.49, 0.00 ± 0.53 and 0.00 ± 0.77 for 10m sprints and 0.00 ± 2.34, 0.00 ± 0.76 and 0.00 ± 0.74 for 30m sprints, non-significant difference in all cases. In conclusion, despite a lower than recommended sample frequency, the WIMU GPS showed to be valid and reliable for measuring sprints at speed higher than 20 km· h-1, as well as for team sport movements. This might be practical on daily physical demands testing during training sessions.