Validity and Reliability of an Accelerometer-Based Player Tracking Device

Nicolella D., Torres-Ronda L., Saylor K., Schelling.

The aim of the Schelling study was to assess the accuracy and reliability of Optimeye S5’s on a shaker table whereby a series of controlled motions were implemented.

Methods:

Measurements in all x,y,z axis were taken at 0.1g@2Hz, 0.5g@3Hz, 1.0g@4Hz, 3.0g@8Hz.
Average peaks were measured over 10 seconds within a 30-second total sample and repeated 5 times (60 tests per device) across 19 units. This was to ensure rig start and end did not influence the results.
The 100Hz accelerometer and Player Load data were exported using Sprint 5.1.7 with device firmware of 7.17.
Player load was manually calculated from our published formula to compare to the ‘actual’ player load output from Sprint.
Results:

Excellent Intra-device reliability (within device) – both mean peak accelerations & Catapult instantaneous Player Load CV ranged from 0.01% to <3.0%. Trivial to extreme effect sizes were found for Inter-device reliability for both PlayerLoad and mean peak acceleration. Differences were observed between Optimeye S5 and the reference accelerometer for mean peak accelerations and Catapult Instantaneous Player Load CV, ranging from 1.0% to 23%. Catapult generated PlayerLoad was 15% lower when compared to the manual calculation using the published formula.

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