THE VALIDITY AND RELIABILITY OF 5-HZ GLOBAL POSITIONING SYSTEM UNITS TO MEASURE TEAM SPORT MOVEMENT DEMANDS

Johnston, RJ, Watsford, ML, Pine, MJ, Spurrs, RW, Murphy, AJ, and Pruyn, EC. The validity and reliability of 5-Hz global positioning system units to measure team sport movement demands. J Strength Cond Res 26(3): 758-765, 2012-The purpose of this research was to investigate the validity and the reliability of 5-Hz MinimaxX global positioning system (GPS) units measuring athlete movement demands. A team sport simulation circuit (files collected from each unit = 12) and flying 50-m sprints (files collected from each unit = 34) were undertaken, during which the total distance covered; peak speed; player load; the distance covered; time spent and number of efforts performed walking, jogging, running, highspeed running, and sprinting were examined. Movement demands were also separately categorized into low-intensity activity, high-intensity running, and very high-intensity running. The results revealed that GPS was a valid and reliable measure of total distance covered (p > 0.05, percentage typical error of measurement [% TEM] <5%) and peak speed (p > 0.05, % TEM 5-10%). Further, GPS was found to be a reliable measure of player load (% TEM 4.9%) and the distance covered, time spent, and number of efforts performed at certain velocity zones (% TEM <5% to >10%). The level of GPS error was found to increase along with the velocity of exercise. The findings demonstrated that GPS is capable of measuring movement demands performed at velocities <20 km.h(-1), whereas more caution is to be exercised when analyzing movement demands collected by using GPS velocities >20 km.h(-1).