{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:38:36Z","timestamp":1760146716597,"version":"build-2065373602"},"reference-count":41,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2024,11,28]],"date-time":"2024-11-28T00:00:00Z","timestamp":1732752000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Knee joint function deterioration significantly impacts quality of life. This study developed estimation models for ten knee indicators using data from in-shoe motion sensors to assess knee movement during everyday activities. Sixty-six healthy young participants were involved, and multivariate linear regression was employed to construct the models. The results showed that eight out of ten models achieved a \u201cfair\u201d to \u201cgood\u201d agreement based on intra-class correlation coefficients (ICCs), with three knee joint angle indicators reaching the \u201cfair\u201d agreement. One temporal indicator model displayed a \u201cgood\u201d agreement, while another had a \u201cfair\u201d agreement. For the angular jerk cost indicators, three out of four attained a \u201cfair\u201d or \u201cgood\u201d agreement. The model accuracy was generally acceptable, with the mean absolute error ranging from 0.54 to 0.75 times the standard deviation of the true values and errors less than 1% from the true mean values. The significant predictors included the sole-to-ground angles, particularly the foot posture angles in the sagittal and frontal planes. These findings support the feasibility of estimating knee function solely from foot motion data, offering potential for daily life monitoring and rehabilitation applications. However, discrepancies in the two models were influenced by the variance in the baseline knee flexion and sensor placement. Future work will test these models on older and osteoarthritis-affected individuals to evaluate their broader applicability, with prospects for user-tailored rehabilitation applications. This study is a step towards simplified, accessible knee health monitoring through wearable technology.<\/jats:p>","DOI":"10.3390\/s24237615","type":"journal-article","created":{"date-parts":[[2024,11,28]],"date-time":"2024-11-28T10:19:42Z","timestamp":1732789182000},"page":"7615","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Estimating Indicators for Assessing Knee Motion Impairment During Gait Using In-Shoe Motion Sensors: A Feasibility Study"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4929-5204","authenticated-orcid":false,"given":"Kazuki","family":"Ihara","sequence":"first","affiliation":[{"name":"Biometrics Research Labs, NEC Corporation, Hinode 1131, Abiko 270-1198, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5516-1982","authenticated-orcid":false,"given":"Chenhui","family":"Huang","sequence":"additional","affiliation":[{"name":"Biometrics Research Labs, NEC Corporation, Hinode 1131, Abiko 270-1198, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2466-3066","authenticated-orcid":false,"given":"Fumiyuki","family":"Nihey","sequence":"additional","affiliation":[{"name":"Biometrics Research Labs, NEC Corporation, Hinode 1131, Abiko 270-1198, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0424-6166","authenticated-orcid":false,"given":"Hiroshi","family":"Kajitani","sequence":"additional","affiliation":[{"name":"Biometrics Research Labs, NEC Corporation, Hinode 1131, Abiko 270-1198, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4803-7182","authenticated-orcid":false,"given":"Kentaro","family":"Nakahara","sequence":"additional","affiliation":[{"name":"Biometrics Research Labs, NEC Corporation, Hinode 1131, Abiko 270-1198, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1002\/pri.280","article-title":"Impact of an Exercise and Walking Protocol on Quality of Life for Elderly People with OA of the Knee","volume":"8","author":"Dias","year":"2003","journal-title":"Physiother. Res. Int."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"619","DOI":"10.2174\/1874325001307010619","article-title":"Quality of Life in Patients with Knee Osteoarthritis: A Commentary on Nonsurgical and Surgical Treatments","volume":"7","author":"Miller","year":"2013","journal-title":"Open Orthop. J."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Toda, H., Maruyama, T., Fujita, K., Yamauchi, Y., and Tada, M. (2021). Self-Reported Walking Difficulty Associated with Stiff-Knee Gait in Japanese Patients with Knee Osteoarthritis: A Preliminary Cross-Sectional Study. Healthcare, 9.","DOI":"10.3390\/healthcare9101308"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1191","DOI":"10.1007\/s00264-014-2312-3","article-title":"Gait Knee Kinematic Alterations in Medial Osteoarthritis: Three Dimensional Assessment","volume":"38","author":"Bytyqi","year":"2014","journal-title":"Int. Orthop."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2255","DOI":"10.3390\/s120202255","article-title":"Gait Analysis Using Wearable Sensors","volume":"12","author":"Tao","year":"2012","journal-title":"Sensors"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"28435","DOI":"10.3390\/s151128435","article-title":"Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life","volume":"15","author":"Tognetti","year":"2015","journal-title":"Sensors"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"B\u00fcttner, C., Milani, T.L., and Sichting, F. (2021). Integrating a Potentiometer into a Knee Brace Shows High Potential for Continuous Knee Motion Monitoring. Sensors, 21.","DOI":"10.3390\/s21062150"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Bolam, S.M., Batinica, B., Yeung, T.C., Weaver, S., Cantamessa, A., Vanderboor, T.C., Yeung, S., Munro, J.T., Fernandez, J.W., and Besier, T.F. (2021). Remote Patient Monitoring with Wearable Sensors Following Knee Arthroplasty. Sensors, 21.","DOI":"10.3390\/s21155143"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.gaitpost.2014.03.189","article-title":"Quantified Self and Human Movement: A Review on the Clinical Impact of Wearable Sensing and Feedback for Gait Analysis and Intervention","volume":"40","author":"Shull","year":"2014","journal-title":"Gait Posture"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Eskofier, B.M., Lee, S.I., Baron, M., Simon, A., Martindale, C.F., Ga\u00dfner, H., and Klucken, J. (2017). An Overview of Smart Shoes in the Internet of Health Things: Gait and Mobility Assessment in Health Promotion and Disease Monitoring. Appl. Sci., 7.","DOI":"10.3390\/app7100986"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"9636","DOI":"10.1109\/JSEN.2022.3164057","article-title":"On-Line Algorithms of Stride-Parameter Estimation for In-Shoe Motion-Sensor System","volume":"22","author":"Fukushi","year":"2022","journal-title":"IEEE Sens. J."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Yaguchi, H., Honda, K., Sekiguchi, Y., Huang, C., Fukushi, K., Wang, Z., Nakahara, K., Kamimura, M., Aki, T., and Ogura, K. (2024). Differences in Kinematic Parameters During Gait Between the Patients with Knee Osteoarthritis and Healthy Controls Using an Insole with a Single Inertial Measurement Unit: A Case-Control Study. Clin. Biomech., 112.","DOI":"10.1016\/j.clinbiomech.2024.106191"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"270","DOI":"10.3109\/03093646.2010.503225","article-title":"The Effects of Tuning an Ankle-Foot Orthosis Footwear Combination on Kinematics and Kinetics of the Knee Joint of an Adult with Hemiplegia","volume":"34","author":"Jagadamma","year":"2010","journal-title":"Prosthet. Orthot. Int."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1515\/hukin-2015-0168","article-title":"Relationships between Movements of the Lower Limb Joints and the Pelvis in Open and Closed Kinematic Chains during a Gait Cycle","volume":"51","author":"Svoboda","year":"2016","journal-title":"J. Hum. Kinet."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.procir.2020.05.132","article-title":"Design of Soft Smart Shoes for Joint Angle Estimation in Human Gait","volume":"89","author":"Yang","year":"2020","journal-title":"Procedia CIRP"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1345","DOI":"10.9734\/BJMMR\/2014\/6067","article-title":"Smoothness of Knee Movement at the Stance Phase in Mild Osteoarthritis of the Knee","volume":"4","author":"Fukaya","year":"2014","journal-title":"Br. J. Med. Med. Res."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1189","DOI":"10.1016\/j.jbiomech.2003.12.005","article-title":"Muscles that Influence Knee Flexion Velocity in Double Support: Implications for Stiff-Knee Gait","volume":"37","author":"Goldberg","year":"2004","journal-title":"J. Biomech."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1097\/01241398-199305000-00010","article-title":"Rectus Femoris Surgery in Children with Cerebral Palsy. Part I: The Effect of Rectus Femoris Transfer Location on Knee Motion","volume":"13","author":"Ounpuu","year":"1993","journal-title":"J. Pediatr. Orthop."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1111","DOI":"10.1016\/S0021-9290(03)00106-4","article-title":"The Importance of Swing-Phase Initial Conditions in Stiff-Knee Gait","volume":"36","author":"Goldberg","year":"2003","journal-title":"J. Biomech."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1097\/01241398-199010040-00001","article-title":"Treatment of Stiff-Knee Gait in Cerebral Palsy: A Comparison by Gait Analysis of Distal Rectus Femoris Transfer Versus Proximal Rectus Release","volume":"10","author":"Sutherland","year":"1990","journal-title":"J. Pediatr. Orthop."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1111\/j.1469-8749.1987.tb02131.x","article-title":"Rectus Femoris Transfer to Improve Knee Function of Children with Cerebral Palsy","volume":"29","author":"Gage","year":"1987","journal-title":"Dev. Med. Child Neurol."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ihara, K., Huang, C., Wang, Z., Nihey, F., Fukushi, K., Kajitani, H., Nozaki, Y., and Nakahara, K. (2023, January 22\u201325). Estimation of Knee Flexion Features Using Foot Motion Data from In-Shoe Motion Sensors. Proceedings of the 2023 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Kuala Lumpur, Malaysia.","DOI":"10.1109\/I2MTC53148.2023.10176068"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"8839","DOI":"10.1109\/JSEN.2023.3248603","article-title":"Feature Selection, Construction, and Validation of a Lightweight Model for Foot Function Assessment During Gait with In-Shoe Motion Sensors","volume":"23","author":"Huang","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Huang, C., Nihey, F., Ihara, K., Fukushi, K., Kajitani, H., Nozaki, Y., and Nakahara, K. (2023). Healthcare Application of In-Shoe Motion Sensor for Older Adults: Frailty Assessment Using Foot Motion During Gait. Sensors, 23.","DOI":"10.3390\/s23125446"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Huang, C., Nihey, F., Fukushi, K., Kajitani, H., Nozaki, Y., Wang, Z., Ihara, K., and Nakahara, K. (2022, January 13\u201315). Assessment Method of Balance Ability of Older Adults Using an In-Shoe Motion Sensor. Proceedings of the 2022 IEEE Biomedical Circuits and Systems Conference (BioCAS), Taipei, Taiwan.","DOI":"10.1109\/BioCAS54905.2022.9948660"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1688","DOI":"10.1523\/JNEUROSCI.05-07-01688.1985","article-title":"The Coordination of Arm Movements: An Experimentally Confirmed Mathematical Model","volume":"5","author":"Flash","year":"1985","journal-title":"J. Neurosci."},{"key":"ref_27","first-page":"1","article-title":"Smoothness of the Knee Joint Movement During the Stance Phase in Patients with Severe Knee Osteoarthritis","volume":"14","author":"Fukaya","year":"2018","journal-title":"Asia-Pac. J. Sports Med. Arthrosc. Rehabil. Technol."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Teufl, W., Miezal, M., Taetz, B., Fr\u00f6hlich, M., and Bleser, G. (2018). Validity, Test-Retest Reliability and Long-Term Stability of Magnetometer Free Inertial Sensor Based 3D Joint Kinematics. Sensors, 18.","DOI":"10.3390\/s18071980"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Madgwick, S.O.H., Harrison, A.J.L., and Vaidyanathan, R. (July, January 29). Estimation of IMU and MARG Orientation Using a Gradient Descent Algorithm. Proceedings of the 2011 IEEE International Conference on Rehabilitation Robotics, Zurich, Switzerland.","DOI":"10.1109\/ICORR.2011.5975346"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Huang, C., Fukushi, K., Wang, Z., Kajitani, H., Nihey, F., and Nakahara, K. (2021). Initial Contact and Toe-Off Event Detection Method for In-Shoe Motion Sensor. Activity and Behavior Computing, Springer.","DOI":"10.1007\/978-981-15-8944-7_7"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1037\/1040-3590.6.4.284","article-title":"Guidelines, Criteria, and Rules of Thumb for Evaluating Normed and Standardized Assessment Instruments in Psychology","volume":"6","author":"Cicchetti","year":"1994","journal-title":"Psychol. Assess."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1037\/0033-2909.112.1.155","article-title":"A Power Primer","volume":"112","author":"Cohen","year":"1992","journal-title":"Psychol. Bull."},{"key":"ref_33","unstructured":"Neumann, D.A. (2010). Kinesiology of the Musculoskeletal System: Foundations of Physical Rehabilitation, Mosby. [2nd ed.]."},{"key":"ref_34","unstructured":"Harris, G.F., and Smith, P.A. (1996). Three-Dimensional Moments Powers and Work in Normal Gait: Implications for Clinical Assessments. Human Motion Analysis: Current Applications and Future Directions, IEEE Press."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"217","DOI":"10.3233\/BMR-181134","article-title":"Gender-Based Age Differences in Hip and Knee Kinematics of Chinese Adults During Walking and Running","volume":"33","author":"Chen","year":"2020","journal-title":"J. Back Musculoskelet. Rehabil."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Inai, T., Kobayashi, Y., Huang, C., Fujita, K., Fujimoto, M., Nihey, F., Yamamoto, A., Nakajima, K., Nakahara, K., and Kutsuzawa, G. (2023). Identification of Characteristics of Foot Position and Angle During Swing Phase in Fallers Using Principal Component Analysis. Front. Bioeng. Biotechnol., 11.","DOI":"10.3389\/fbioe.2023.1117884"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1682\/JRRD.1985.07.0085","article-title":"Electromyographic Patterns in Adult Locomotion: A Comprehensive Review","volume":"22","author":"Shiavi","year":"1985","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1002\/acr.20012","article-title":"Knee Joint Stiffness During Walking in Knee Osteoarthritis","volume":"62","author":"Dixon","year":"2010","journal-title":"Arthritis Care Res."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Ezaki, S., Kadone, H., Kubota, S., Abe, T., Shimizu, Y., Tan, C.K., Miura, K., Hada, Y., Sankai, Y., and Koda, M. (2021). Analysis of Gait Motion Changes by Intervention Using Robot Suit Hybrid Assistive Limb (HAL) in Myelopathy Patients After Decompression Surgery for Ossification of Posterior Longitudinal Ligament. Front. Neurorobot., 15.","DOI":"10.3389\/fnbot.2021.650118"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"629","DOI":"10.2519\/jospt.2016.6618","article-title":"Hip Strength Deficits in People with Symptomatic Knee Osteoarthritis: A Systematic Review with Meta-Analysis","volume":"46","author":"Deasy","year":"2016","journal-title":"J. Orthop. Sports Phys. Ther."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Fukaya, T., Mutsuzaki, H., and Wadano, Y. (2013). Smoothness Using Angular Jerk Cost of the Knee Joint Movement After a Reduction in Walking Speed. J. Mech. Med. Biol., 13.","DOI":"10.1142\/S0219519413500371"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/23\/7615\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:41:54Z","timestamp":1760114514000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/23\/7615"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,11,28]]},"references-count":41,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2024,12]]}},"alternative-id":["s24237615"],"URL":"https:\/\/doi.org\/10.3390\/s24237615","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2024,11,28]]}}}