Criterion Validity of Catapult ClearSky T6 Local Positioning System for Measuring Inter-Unit Distance

Hodder R.W., Ball K.A., Serpiello F.R.

The validity of a local positioning system (LPS) to measure inter-unit distance was
investigated during a team sport movement circuit. Eight recreationally active, female indoor
team-sport players completed a circuit, comprising seven types of movements (walk, jog, jump, sprint,
45° change of direction, and shuffle), on an indoor court. Participants wore a receiver tag (ClearSky T6,
Catapult Sports) and seven reflective markers, to allow for a comparison with the reference system
(©Vicon Motion Systems, Oxford Metrics, UK). Inter-unit distance was collected for each combination
of participants. Validity was assessed via root mean square error, mean bias, and percentage of
variance accounted for, both as an overall dataset and split into distance bands. The results presented
a mean root mean square error of 0.20 ± 0.05 m, and mean bias detected an overestimation for all
distance bands. The LPS shows acceptable accuracy for measuring inter-unit distance, opening up
opportunities to utilize player tracking for tactical variables indoors.

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