The Reliability and Criterion Validity of Catapult S5 and Statsports Viper GPS Devices for Measuring Movement Demands in Open Environments

Bowen L., Adkin N., Lib F.X., Harley J., Ainsley S., Brice P.

Purpose: The aims of the current study were to compare the accuracy and reliability of two different brands of GPS device during field-based tests.

Methods: Three team sport players (Mean ±SD; age: 26 ± 1 yr; height: 1.80 ± 0.08 m; body mass: 85.6 ± 13.6 kg) completed 5 tests involving linear and multidirectional movement. The tests selected were an 80m square run (SR), 25m change of direction (COD25), 12.5m change of direction (COD12.5), 10m sprints (SP10), and 10m return sprints (SPR10). Each test was repeated a minimum of 6 times. One participant wore one GPS device (D1; Viper, Statsports), the second participant wore another GPS device (D2; S5, Catapult Sports), with the third participant wearing a custom-designed garment housing both units. Units were swapped between participants between trials. For linear trials, a speed gun (laveg) was used as a criterion measure. Unit reliability (CV%) and criterion validity (bias, std bias) were determined for each system for each trial.

Results: Results from both systems demonstrated lower reliability and validity on the more challenging trials. The S5 (CV% 2.8-10.3) showed greater reliability than the Viper system (CV% 4.4-15.5) in all but the COD12.5 trials. The results from the S5 were closer to the criterion value for distance (bias 2.5 to -16.8%) than those for the Viper (bias -3.7 to -22%) in all trials, and for maximum velocity data (mean bias 0.21 vs. 0.8 m.s-1).

Conclusions: Shorter runs with high concentrations of change of direction movement place greater challenges on the ability of GPS to report accurately and reliably. In such circumstances, different systems report different data and are thus not interchangeable. The Catapult S5 GPS system generates data, which possesses greater reliability and validity than the Statsports Viper GPS system.

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