Accuracy and reliability of SPI ProX global positioning system devices for measuring movement demands of team sports

Abstract

Aim: The aim of this study was to determine the accuracy and reliability of SPI ProX global positioning system (GPS) devices for measuring movement at various speeds and movement patterns as evident in team sport demands. Methods: Eleven amateur soccer players performed a 40 m straight sprint test (with 10-20-30 m split times), a zigzag test, 30 m walking, jogging and moderate intensity runs. Results: Results indicated that the SPI ProX GPS measurements showed acceptable accuracy for all movement patterns for distance (coefficient of variation [CV]=0.14% to 3.73%; 95% ratio limits of agreement [95% ratio LOA]=0.97 x/÷ 1.09 to 1.00 x/÷ 1.05) and speed (CV=4.22% to 9.52%; 95%LOA=-0.17±1.70 km h-1 to 2.30±1.17 km h-1) compared with the measured distance and speed determined from timing gates, respectively. Furthermore, acceptable reliability of SPI ProX GPS measures for distance (CV=0.34% to 3.81%; 95%LOA=-0.09±0.23 m to -0.34±2.31 m) and speed (CV=3.19% to 6.95%;95%LOA=-0.05±3.90 km h-1 to 0.42±3.68 km h-1) were also evident. Conclusion: Whilst SPI ProX GPS devices were within acceptable ranges of reliability, they remained signiicantly different to criterion measures of team sport movement demands.