Validity of gait parameters of healthy young adults using a motion-sensor-based gait analysis system (ORPHE ANALYTICS) during walking and running

Background Motion sensors are widely used for gait analysis. ORPHE ANALYTICS is a motion-sensor-based gait analysis system. The validity of commercial gait analysis systems is of great interest to clinicians because calculating position/angle-level gait parameters using motion sensor data potentially produces an error in the integration process; moreover, the validity of ORPHE ANALYTICS has not yet been examined. Research question How valid are the position/angle-level gait parameters calculated using ORPHE ANALYTICS relative to those calculated using conventional optical motion capture? Methods Nine young adults performed gait tasks on a treadmill at speeds of 2–12 km/h. The motion sensors were mounted on the shoe midsole (plantar-embedded) and shoe instep (instep-mounted). The three-dimensional marker position data of the foot as well as the acceleration and angular velocity data of the motion sensors were collected. The position/angle-level gait parameters were calculated from motion sensor data obtained using ORPHE ANALYTICS and optical motion capture data. Intraclass correlation coefficients [ICC(2,1)] were calculated for relative validities, and Bland–Altman plots were plotted. Results Eight items, namely, stride duration, stride length, stride frequency, stride speed (plantar-embedded), vertical height (plantar-embedded), stance phase duration, swing phase duration, and sagittal angleIC, exhibited excellent relative validities [ICC(2,1) > 0.9]. In contrast, the sagittal angleTO demonstrated good relative validity [ICC(2,1) = 0.892–0.833], while the frontal angleIC exhibited moderate relative validity [ICC(2,1) = 0.566–0.627]. Significance ORPHE ANALYTICS, a motion-sensor-based gait analysis system, was found to exhibit excellent relative validity for most gait parameters. This finding suggests its feasibility for gait analysis outside the laboratory setting. Highlights ### Competing Interest Statement Conflicts of Interest Statement UY is an employee of ORPHE, Inc., which provided the ORPHE ANALYTICS. OI, KS, and TA are affiliated with the Department of Sports Medical Biomechanics, Graduate School of Medicine, Osaka University, which is supported by ORPHE, Inc. YN is a part-time employee at ORPHE, Inc. KN received a research grant from ORPHE, Inc. ### Funding Statement This work was supported by MEXT "Innovation Platform for Society 5.0" Program Grant Number JPMXP0518071489. The funder had no role in the study design, collection, analysis, and interpretation of data, manuscript preparation, and decision to submit the article for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Osaka University Hospital Ethics Committee approved this study (approval no. 19537), and all participants provided informed consent. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors