Concurrent validation of the Noraxon MyoMotion wearable inertial sensors in change-of-direction and jump-landing tasks

ABSTRACTWearable inertial sensors (WIS) facilitate the preservation of the athlete-environment relationship by allowing measurement outside the laboratory. WIS systems should be validated for team sports movements before they are used in sports performance and injury prevention research. The aim of the present study was to investigate the concurrent validity of a wearable inertial sensor system in quantifying joint kinematics during team sport movements. Ten recreationally active participants performed change-of-direction (single-leg deceleration and sidestep cut) and jump-landing (single-leg hop, single-leg crossover hop, and double-leg vertical jump) tasks while motion was recorded by nine inertial sensors (Noraxon MyoMotion, Noraxon USA Inc.) and eight motion capture cameras (Vicon Motion Systems Ltd). Validity of lower-extremity joint kinematics was assessed using measures of agreement (cross-correlation: XCORR) and error (root mean square deviation; and amplitude difference). Excellent agreement (XCORR >0.88) was found for sagittal plane kinematics in all joints and tasks. Highly variable agreement was found for frontal and transverse plane kinematics at the hip and ankle. Errors were relatively high in all planes. In conclusion, the WIS system provides valid estimates of sagittal plane joint kinematics in team sport movements. However, researchers should correct for offsets when comparing absolute joint angles between systems.KEYWORDS: Wearable inertial sensorsoptoelectronic marker-based systemmotion capture validationchange-of-directionjump-landing AcknowledgmentsThe authors would like to thank Jurgen Hoorn and Harmen Vlietstra for their support in data acquisition.Author contributionsConceptualization, P.H., A.B., R.B. and A.G.; methodology P.H., A.B., R.B. and A.G.; software, E.O.; validation, P.H., A.B., R.B. and A.G.; formal analysis, P.H., R.B. and E.O.; investigation, P.H., A.B., R.B. and A.G.; resources, A.B., J.B. and A.G.; data curation, P.H., R.B. and E.O.; writing—original draft preparation, P.H.; writing—review and editing, A.B., R.B., J.B., E.O. and A.G.; visualisation, P.H., A.B., R.B. and A.G.; supervision, A.B., J.B. and A.G.; project administration, A.B., J.B. and A.G. All authors have read and agreed to the published version of the manuscript.Data availability statementThe data presented in this study are available on reasonable request. The data are not publicly available due to privacy restrictions.Disclosure statementNo potential conflict of interest was reported by the author(s).Informed consent statementInformed consent was obtained from all subjects involved in the study.Institutional review board statementProcedures were approved by the institutional Medical Ethics Committee (IRB nr. 2018/249).Additional informationFundingThe author(s) reported there is no funding associated with the work featured in this article.