Validity and reliability of an accelerometer-based player tracking device

Area of Science:

• Sports Science
• Biomechanics
• Wearable Technology

Background:

• Wearable athletic tracking devices are increasingly used in sports for performance monitoring.
• Understanding the accuracy and reliability of these devices is crucial for valid data interpretation.
• Previous research has not comprehensively assessed the intra- and inter-device reliability of specific accelerometers under controlled conditions.

Purpose of the Study:

• To determine the intra- and inter-device accuracy and reliability of wearable athletic tracking devices (Catapult OptimEye S5).
• To evaluate device performance under controlled laboratory conditions using controlled oscillations.
• To compare Catapult PlayerLoad™ with player load calculated using a Cartesian formula.

Main Methods:

• Nineteen Catapult OptimEye S5 accelerometers were subjected to controlled oscillations in three orthogonal directions at four acceleration levels.
• Data was recorded at 100Hz, with peak accelerations and PlayerLoad™ metrics analyzed.
• Intra- and inter-device reliability was assessed using effect sizes and intraclass correlation coefficients (ICCs).

Main Results:

• Devices demonstrated excellent intra-device reliability (ICCs ranging from 0.77 to 1.0).
• Inter-device reliability was mixed, with significant differences in mean peak accelerations and PlayerLoad™ across devices.
• Catapult PlayerLoad™ was consistently ~15% lower than the player load calculated using the Cartesian formula.

Conclusions:

• While individual devices are reliable, significant variability exists between different units.
• The consistent underestimation of PlayerLoad™ by the device warrants attention.
• Industry-wide standards for reporting validity, reliability, and measurement errors are essential; periodic quantification of device accuracy is recommended.