Validity and reliability of 5 Hz GPS devices on short career with change of direction

The aim of this study was to assess the validity and reliability of a MinimaxX GPS device (Team Sport 2.5, Catapult Innovations) operating with a sampling frequency of 5 Hz. Were measured distances made for 10 football players (age, 22.5 ±2.9 years, height 174 ±7 cm. and weight 72.6 ±3.4 kg) in the specific Yo-Yo Endurance Test level 1. The test ended when the players completed the first 10 levels of speed test (from 2.22 to 3.48 m·s-1). Four of the 10 participants took two simultaneously GPS, what allowed to value the reliability of the devices. In the validity study comparing the values obtained by the GPS with the actual values obtained by tape before performing the test. Statistical analysis were: coefficient of variation (1 – 17 %), standard error (2.3 – 136 m), standard error estimated, (5 – 11 %) and means difference (-0.7 – 89.2 m). The results indicate that although the reliability and validity showed satisfactory results at moderate intensities, almost all levels and for the total distance, although the distance was overestimated