Reliability of Wearable Inertial Measurement Units to Measure Physical Activity in Team Handball

Luteberget L.S., Holme B.R., Spencer M.

Purpose:
This study aimed to evaluate the reliability and sensitivity of commercially available inertial measurement units (IMUs) in measuring physical activity in team handball.

Method:
Twenty-two handball players were equipped with two IMUs (OptimEye S5, Catapult Sports, Australia) taped together. Two assessments were conducted: a laboratory assessment involving seven team handball specific tasks with ten participants, and a field assessment during twelve training sessions with twelve participants. Variables including PlayerLoadTM and inertial movement analysis (IMA) magnitude and counts were extracted from the manufacturer’s software. IMA count was categorized into intensity bands of low (1.5-2.5 m/s), medium (2.5-3.5 m/s), high (>3.5 m/s), medium/high (>2.5 m/s), and total (>1.5 m/s). Reliability between devices and sensitivity was established using the coefficient of variation (CV) and smallest worthwhile difference (SWD).

Results:

Laboratory assessment: IMA magnitude demonstrated good reliability (CV: 3.1%) in well-controlled tasks, with increased CV in more complex tasks (4.4-6.7%).
Field assessment: Total IMA count (CV: 1.8%, SWD: 2.5%), PlayerLoadTM (CV: 0.9%, SWD: 2.1%), and associated variables (CV: 0.4-1.7%) showed good reliability, well below the SWD. However, the CV of IMA increased when categorized into intensity bands (2.9-5.6%).
Conclusion:

IMA count demonstrated good reliability when data was displayed as total, high, or medium/high counts.
PlayerLoadTM and associated variables exhibited good reliability with CV values well below the SWD.
The OptimEye IMU and its software showed sensitivity for use in team handball based on the reliability and sensitivity metrics evaluated.

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