Quantifying the Physical Demands of Collision Sports: Does Microsensor Technology Measure What It Claims to Measure?

Gabbett, T.J.

Background: The physical demands of rugby league, rugby union, and American football are significantly increased through the large number of collisions players are required to perform during match play. Because of the labor-intensive nature of coding collisions from video recordings, manufacturers of wearable microsensor (e.g., global positioning system [GPS]) units have refined the technology to automatically detect collisions, with several sport scientists attempting to use these microsensors to quantify the physical demands of collision sports. However, a question remains over the validity of these microtechnology units to quantify the contact demands of collision sports. Recent evidence has shown significant differences in the number of “impacts” recorded by microtechnology units (GPSports) and the actual number of collisions coded from video.

Objective: The objective of this study was to investigate the validity of microtechnology units in quantifying the contact loads typical in collision sports, focusing on the comparison between microsensor-detected collisions and those coded from video recordings.

Methods: A separate study investigated the validity of a different microtechnology unit (minimaxX; Catapult Sports) that included GPS and triaxial accelerometers, as well as a gyroscope and magnetometer, to quantify collisions. Collisions detected by the minimaxX unit were compared with video-based coding of the actual events.

Results: No significant differences were detected in the number of mild, moderate, and heavy collisions detected via the minimaxX units and those coded from video recordings of the actual event. Furthermore, a strong correlation (r = 0.96, p < 0.01) was observed between collisions recorded via the minimaxX units and those coded from video recordings of the event. These findings suggest that the minimaxX unit can be considered capable of offering a valid method of quantifying the contact loads that typically occur in collision sports. Conclusion: Until further validation research is completed, sport scientists should be cautious of the ability of other units to perform similar functions.

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