The Validity and Between-Unit Variability of GNSS Units (STATSports Apex 10 and 18 Hz) for Measuring Distance and Peak Speed in Team Sports

Beato M., Coratella G., Stiff A., Dello Iacono A.

Aims: This study aimed to (i) investigate the criterion validity of the 10 and 18 Hz STATSports Apex units for measuring distances and peak speed (Vpeak) compared to gold standard measurements, and (ii) evaluate the between-unit variability.

Participants: Twenty university students (age 21 ± 2 years, weight 72 ± 6 kg, height 1.76 ± 0.05 m).

Methods:

Criterion Validity: The distances recorded by the Apex units were compared with ground truth reference distances in three trials: a 400-m trial, a 128.5-m circuit, and a 20-m trial.
Peak Speed Validity: Vpeak values were compared with those determined by a gold standard criterion device (Stalker ATS Radar Gun) during a linear 20-m sprint.
Results:

Distance Biases:
Apex 10 Hz:
400-m trial: 1.05 ± 0.87%
128.5-m circuit: 2.3 ± 1.1%
20-m trial: 1.11 ± 0.99%
Apex 18 Hz:
400-m trial: 1.17 ± 0.73%
128.5-m circuit: 2.11 ± 1.06%
20-m trial: 1.15 ± 1.23%
Vpeak Measurements:
Apex 10 Hz: 26.5 ± 2.3 km/h
Apex 18 Hz: 26.5 ± 2.6 km/h
Criterion Method (Stalker ATS Radar Gun): 26.3 ± 2.4 km/h
Vpeak Bias:
Apex 10 Hz: 2.36 ± 1.67%
Apex 18 Hz: 2.02 ± 1.24%
Between-unit Analysis: T-tests for total distance and Vpeak reported non-significant differences between the units.
Conclusions: Both the 10 Hz and 18 Hz STATSports Apex units demonstrated small errors (around 1-2%) compared to the criterion distances and Vpeak measurements during the trials. These findings suggest that both units can be used with confidence to measure these variables during training and match play.