{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T11:04:33Z","timestamp":1789383873770,"version":"build-2803163510"},"reference-count":28,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T00:00:00Z","timestamp":1789344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"SPLYZA Inc."}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This study aimed to conduct an initial validation of markerless gait analysis using SPLYZA Motion by evaluating waveform agreement under practical measurement conditions. Joint angle waveforms were compared with those obtained from a marker-based motion capture system. SPLYZA Motion was found to be in good waveform agreement with the reference system for trunk and proximal lower-limb kinematics. Larger errors were observed in distal joints, particularly under occlusion and higher cadence; however, these differences were phase-dependent and did not substantially affect overall waveform patterns. These findings suggest that SPLYZA Motion may serve as a complementary tool for repeated waveform-based gait assessments under practical measurement conditions. Further validation in larger and more diverse populations is required before broader clinical application can be considered.<\/jats:p>","DOI":"10.3390\/s26185809","type":"journal-article","created":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T10:19:41Z","timestamp":1789381181000},"page":"5809","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Initial Validation of Markerless Gait Analysis Using SPLYZA Motion: Waveform Agreement Under Practical Measurement Conditions"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9920-9442","authenticated-orcid":false,"given":"Yu","family":"Inoue","sequence":"first","affiliation":[{"name":"School of Human Science, Kibi International University, Takahashi 716-8508, Japan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4143-9661","authenticated-orcid":false,"given":"Ryo","family":"Yamasaki","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation, Kurashiki Heisei Hospital, Kurashiki 710-0826, Japan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6526-2149","authenticated-orcid":false,"given":"Koji","family":"Ono","sequence":"additional","affiliation":[{"name":"Graduate School of Humanities and Social Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0560-0702","authenticated-orcid":false,"given":"Shunsuke","family":"Yamashina","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, Shimane University, Izumo 693-8501, Japan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5920-8705","authenticated-orcid":false,"given":"Kiyofumi","family":"Ando","sequence":"additional","affiliation":[{"name":"SPLYZA Inc., Hamamatsu 430-0805, Japan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Hiroyuki","family":"Doi","sequence":"additional","affiliation":[{"name":"SPLYZA Inc., Hamamatsu 430-0805, Japan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Stotz, A., Hamacher, D., and Zech, A. (2023). Relationship between Muscle Strength and Gait Parameters in Healthy Older Women and Men. Int. J. Environ. Res. Public Health, 20.","DOI":"10.3390\/ijerph20075362"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"M303","DOI":"10.1093\/gerona\/51A.6.M303","article-title":"Step length reductions in advanced age: The role of ankle and hip kinetics","volume":"51","author":"Judge","year":"1996","journal-title":"J. Gerontol. A Biol. Sci. Med. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/j.gaitpost.2018.06.012","article-title":"Do spatiotemporal parameters and gait variability differ across the lifespan of healthy adults? A systematic review","volume":"64","author":"Herssens","year":"2018","journal-title":"Gait Posture"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.exger.2017.05.005","article-title":"Systematic review and meta-analysis of gait mechanics in young and older adults","volume":"95","author":"Boyer","year":"2017","journal-title":"Exp. Gerontol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"112102","DOI":"10.1016\/j.exger.2023.112102","article-title":"Age-related changes in gait biomechanics and their impact on the metabolic cost of walking: Report from a National Institute on Aging workshop","volume":"173","author":"Boyer","year":"2023","journal-title":"Exp. Gerontol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1111\/j.1532-5415.2005.00580.x","article-title":"Epidemiology of gait disorders in community-residing older adults","volume":"54","author":"Verghese","year":"2006","journal-title":"J. Am. Geriatr. Soc."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Guo, Y., Yang, J., Liu, Y., Chen, X., and Yang, G.Z. (2022). Detection and assessment of Parkinson\u2019s disease based on gait analysis: A survey. Front. Aging Neurosci., 14.","DOI":"10.3389\/fnagi.2022.916971"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Diraco, G., Manni, A., and Leone, A. (2023). Integrating Abnormal Gait Detection with Activities of Daily Living Monitoring in Ambient Assisted Living: A 3D Vision Approach. Sensors, 24.","DOI":"10.3390\/s24010082"},{"key":"ref_9","first-page":"128","article-title":"The assessment of gait disorders in patients with Parkinson\u2019s disease using the three-dimensional motion analysis system Vicon","volume":"41","author":"Mirek","year":"2007","journal-title":"Neurol. Neurochir. Pol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"102314","DOI":"10.1016\/j.artmed.2022.102314","article-title":"A comprehensive survey on gait analysis: History, parameters, approaches, pose estimation, and future work","volume":"129","author":"Sethi","year":"2022","journal-title":"Artif. Intell. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1878","DOI":"10.1016\/S0003-9993(03)00482-9","article-title":"The status of gait assessment among physiotherapists in the United Kingdom","volume":"84","author":"Toro","year":"2003","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Stenum, J., Hsu, M.M., Pantelyat, A.Y., and Roemmich, R.T. (2024). Clinical gait analysis using video-based pose estimation: Multiple perspectives, clinical populations, and measuring change. PLoS Digit. Health, 3.","DOI":"10.1371\/journal.pdig.0000467"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Uhlrich, S.D., Falisse, A., Kidzi\u0144ski, \u0141., Muccini, J., Ko, M., Chaudhari, A.S., Hicks, J.L., and Delp, S.L. (2023). OpenCap: Human movement dynamics from smartphone videos. PLoS Comput. Biol., 19.","DOI":"10.1371\/journal.pcbi.1011462"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"110665","DOI":"10.1016\/j.jbiomech.2021.110665","article-title":"Concurrent assessment of gait kinematics using marker-based and markerless motion capture","volume":"127","author":"Kanko","year":"2021","journal-title":"J. Biomech."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1168","DOI":"10.1016\/j.medengphy.2014.07.007","article-title":"Markerless motion capture can provide reliable 3D gait kinematics in the sagittal and frontal plane","volume":"36","author":"Sandau","year":"2014","journal-title":"Med. Eng. Phys."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"109929","DOI":"10.1016\/j.jbiomech.2020.109929","article-title":"Reliability of a markerless motion capture system to measure the trunk, hip and knee angle during walking on a flatland and a treadmill","volume":"109","author":"Tamura","year":"2020","journal-title":"J. Biomech."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1016\/j.jbiomech.2018.01.035","article-title":"Validity of time series kinematical data as measured by a markerless motion capture system on a flatland for gait assessment","volume":"71","author":"Tanaka","year":"2018","journal-title":"J. Biomech."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.medengphy.2017.03.007","article-title":"Microsoft Kinect can distinguish differences in over-ground gait between older persons with and without Parkinson\u2019s disease","volume":"44","author":"Eltoukhy","year":"2017","journal-title":"Med. Eng. Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"274","DOI":"10.3109\/03091902.2014.909540","article-title":"Comparative abilities of Microsoft Kinect and Vicon 3D motion capture for gait analysis","volume":"38","author":"Pfister","year":"2014","journal-title":"J. Med. Eng. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"106613","DOI":"10.1016\/j.dib.2020.106613","article-title":"Lower limb kinematic, kinetic and spatial-temporal gait data for healthy adults using a self-paced treadmill","volume":"34","author":"Bahadori","year":"2021","journal-title":"Data Brief."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"107915","DOI":"10.1016\/j.dib.2022.107915","article-title":"Dataset of energetics and biomechanics of self-paced and fixed speed treadmill walking at multiple speeds","volume":"41","author":"Theunissen","year":"2022","journal-title":"Data Brief."},{"key":"ref_22","unstructured":"Japanese Orthopaedic Association, Japanese Association of Rehabilitation Medicine, and Japanese Society for Surgery of the Foot (2026, May 31). Range of Motion Measurement Guidelines. Available online: https:\/\/www.jspo.jp\/pdf\/rangeofmotion2022.pdf."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"383","DOI":"10.1002\/jor.1100080310","article-title":"Measurement of lower extremity kinematics during level walking","volume":"8","author":"Kadaba","year":"1990","journal-title":"J. Orthop. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"540","DOI":"10.1016\/j.gaitpost.2010.02.009","article-title":"A new formulation of the coefficient of multiple correlation to assess the similarity of waveforms measured synchronously by different motion analysis protocols","volume":"31","author":"Ferrari","year":"2010","journal-title":"Gait Posture"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1016\/j.gaitpost.2025.04.016","article-title":"Reliability and validity of current computer vision based motion capture systems in gait analysis: A systematic review","volume":"120","author":"Cheng","year":"2025","journal-title":"Gait Posture"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Pham, Q.-T., Nguyen, D.-A., Nguyen, T.-T., Nguyen, T.N., Nguyen, D.-T., Pham, D.-T., Tran, T.H., Le, T.-L., and Vu, H. (2022). A Study on Skeleton-Based Action Recognition and Its Application to Physical Exercise Recognition, Association for Computing Machinery.","DOI":"10.1145\/3568562.3568639"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"656","DOI":"10.1177\/00187208241309748","article-title":"Video-Based Lifting Action Recognition Using Rank-Altered Kinematic Feature Pairs","volume":"67","author":"Jung","year":"2025","journal-title":"Hum. Factors"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1177\/00187208261418858","article-title":"Toward a Fully Automated NIOSH Lifting Equation Using Computer Vision","volume":"68","author":"Jung","year":"2026","journal-title":"Hum. Factors"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/18\/5809\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T10:23:59Z","timestamp":1789381439000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/18\/5809"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,14]]},"references-count":28,"journal-issue":{"issue":"18","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["s26185809"],"URL":"https:\/\/doi.org\/10.3390\/s26185809","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,14]]}}}