The Validity and Reliability of Global Positioning System Units for Measuring Distance and Velocity During Linear and Team Sport Simulated Movements

Huggins, RA, Giersch, GEW, Belval, LN, Benjamin, CL, Curtis, RM, Sekiguchi, Y, Peltonen, J, and Casa, DJ. The validity and reliability of GPS units for measuring distance and velocity during linear and team sport simulated movements. J Strength Cond Res 34(11): 3070-3077, 2020-This experimental study aimed to assess the validity and reliability of shirt-mounted 10-Hz global positioning system (GPS) units (Polar Team Pro) for measuring total distance (TD), constant velocity (Vel(C)), and instantaneous velocity (Vel(I)) during linear running and a team sport simulation circuit (TSSC). Fifteen male soccer athletes completed linear tasks (40 and 100 m) at various velocities: walk (W) (4.8-7.9 km center dot h(-1)), jog (J) (8.0-12.7 km center dot h(-1)), run (R) (12.9-19.9 km center dot h(-1)), and sprint (S) (>20.0 km center dot h(-1)) and a 120-m TSSC. Global positioning system validity and reliability for TD, Vel(C), and Vel(I) were compared with criterion measures using 2 methods (a and b) of GPS raw data extraction. When measuring TD for the Polar Team Pro device, validity and reliability measures were <5% error at all velocities during the 40-m (with the exception of the S [%CV = 8.03]) and 100-m linear trial (both extraction methods) and TSSC. The GPS mean difference (+/- SD) for TD during the TSSC using extraction methods (a) and (b) was 0.2 +/- 1.2 and 2.2 +/- 2.2 m, respectively. The validity of the device in measuring Vel(C) was significantly different (p < 0.05) at all velocities during the 40 m (exception W) and the 100 m, with effect sizes ranging from trivial to small (exception of 100 m S). Vel(I) was similar (p > 0.05) at all velocities, except for the W (p = 0.001). The reliability of the device when measuring Vel(C) during the 40 and 100 m was <5% CV; however, during the 100 m, Vel(I) ranged from 1.4 to 12.9%. Despite trivial to large effect sizes for validity of TD, this device demonstrated good reliability <5% CV during linear and TSSC movements. Similarly, effect sizes ranged from trivial to large for Vel(C,) and yet Vel(I) reliability was good for Vel(C), but good to poor for Vel(I).