{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T07:59:59Z","timestamp":1773734399895,"version":"3.50.1"},"reference-count":49,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,2,11]],"date-time":"2020-02-11T00:00:00Z","timestamp":1581379200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100008982","name":"Qatar National Research Fund","doi-asserted-by":"publisher","award":["UREP23-031-2-014"],"award-info":[{"award-number":["UREP23-031-2-014"]}],"id":[{"id":"10.13039\/100008982","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Research University Grant","award":["DIP-2018-017"],"award-info":[{"award-number":["DIP-2018-017"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Gait analysis is a systematic study of human locomotion, which can be utilized in various applications, such as rehabilitation, clinical diagnostics and sports activities. The various limitations such as cost, non-portability, long setup time, post-processing time etc., of the current gait analysis techniques have made them unfeasible for individual use. This led to an increase in research interest in developing smart insoles where wearable sensors can be employed to detect vertical ground reaction forces (vGRF) and other gait variables. Smart insoles are flexible, portable and comfortable for gait analysis, and can monitor plantar pressure frequently through embedded sensors that convert the applied pressure to an electrical signal that can be displayed and analyzed further. Several research teams are still working to improve the insoles\u2019 features such as size, sensitivity of insoles sensors, durability, and the intelligence of insoles to monitor and control subjects\u2019 gait by detecting various complications providing recommendation to enhance walking performance. Even though systematic sensor calibration approaches have been followed by different teams to calibrate insoles\u2019 sensor, expensive calibration devices were used for calibration such as universal testing machines or infrared motion capture cameras equipped in motion analysis labs. This paper provides a systematic design and characterization procedure for three different pressure sensors: force-sensitive resistors (FSRs), ceramic piezoelectric sensors, and flexible piezoelectric sensors that can be used for detecting vGRF using a smart insole. A simple calibration method based on a load cell is presented as an alternative to the expensive calibration techniques. In addition, to evaluate the performance of the different sensors as a component for the smart insole, the acquired vGRF from different insoles were used to compare them. The results showed that the FSR is the most effective sensor among the three sensors for smart insole applications, whereas the piezoelectric sensors can be utilized in detecting the start and end of the gait cycle. This study will be useful for any research group in replicating the design of a customized smart insole for gait analysis.<\/jats:p>","DOI":"10.3390\/s20040957","type":"journal-article","created":{"date-parts":[[2020,2,11]],"date-time":"2020-02-11T11:45:30Z","timestamp":1581421530000},"page":"957","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":112,"title":["A Systematic Approach to the Design and Characterization of a Smart Insole for Detecting Vertical Ground Reaction Force (vGRF) in Gait Analysis"],"prefix":"10.3390","volume":"20","author":[{"given":"Anas M.","family":"Tahir","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0744-8206","authenticated-orcid":false,"given":"Muhammad E. H.","family":"Chowdhury","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7068-9112","authenticated-orcid":false,"given":"Amith","family":"Khandakar","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]},{"given":"Sara","family":"Al-Hamouz","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]},{"given":"Merna","family":"Abdalla","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]},{"given":"Sara","family":"Awadallah","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]},{"given":"Mamun Bin Ibne","family":"Reaz","sequence":"additional","affiliation":[{"name":"Department of Electrical, Electronic &amp; Systems Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, Malaysia"}]},{"given":"Nasser","family":"Al-Emadi","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Qatar University, Doha 2713, Qatar"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.gaitpost.2018.10.008","article-title":"Side does not matter in healthy young and older individuals\u2013Examining the importance of how we match limbs during gait studies","volume":"67","author":"Kowalski","year":"2019","journal-title":"Gait Posture"},{"key":"ref_2","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_3","doi-asserted-by":"crossref","first-page":"3284","DOI":"10.1109\/TBME.2013.2250972","article-title":"Kinetic gait analysis using a low-cost insole","volume":"60","author":"Howell","year":"2013","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1109\/TITB.2007.899493","article-title":"Gait analysis using a shoe-integrated wireless sensor system","volume":"12","author":"Bamberg","year":"2008","journal-title":"IEEE Trans. Inf. Technol. Biomed."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"De Rossi, S., Lenzi, T., Vitiello, N., Donati, M., Persichetti, A., Giovacchini, F., Vecchi, F., and Carrozza, M.C. (September, January 30). Development of an in-shoe pressure-sensitive device for gait analysis. Proceedings of the 2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Boston, MA, USA.","DOI":"10.1109\/IEMBS.2011.6091364"},{"key":"ref_6","unstructured":"(2020, February 09). Smart Tracking and Wearables: Techniques in Gait Analysis and Movement in Pathological Aging. Available online: https:\/\/www.intechopen.com\/books\/smart-healthcare\/smart-tracking-and-wearables-techniques-in-gait-analysis-and-movement-in-pathological-aging."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Gurchiek, R.D., Choquette, R.H., Beynnon, B.D., Slauterbeck, J.R., Tourville, T.W., Toth, M.J., and McGinnis, R.S. (2019, January 19\u201322). Remote gait analysis using wearable sensors detects asymmetric gait patterns in patients recovering from ACL reconstruction. Proceedings of the 2019 IEEE 16th International Conference on Wearable and Implantable Body Sensor Networks (BSN), Chicago, IL, USA.","DOI":"10.1109\/BSN.2019.8771038"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Brognara, L., Palumbo, P., Grimm, B., and Palmerini, L. (2019). Assessing gait in parkinson\u2019s disease using wearable motion sensors: A systematic review. Diseases, 7.","DOI":"10.3390\/diseases7010018"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1504","DOI":"10.1016\/j.jbiomech.2006.06.017","article-title":"Repeatability of 3D gait kinematics obtained from an electromagnetic tracking system during treadmill locomotion","volume":"40","author":"Mills","year":"2007","journal-title":"J. Biomech."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"ATP173","DOI":"10.1161\/str.50.suppl_1.TP173","article-title":"Abstract TP173: Feasibility and Utility of Home-Based Gait Analysis Using Body-Worn Sensors","volume":"50","author":"Huang","year":"2019","journal-title":"Stroke"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"10240","DOI":"10.3390\/s101110240","article-title":"A wearable ground reaction force sensor system and its application to the measurement of extrinsic gait variability","volume":"10","author":"Liu","year":"2010","journal-title":"Sensors"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"9884","DOI":"10.3390\/s120709884","article-title":"Foot plantar pressure measurement system: A review","volume":"12","author":"Razak","year":"2012","journal-title":"Sensors"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1253","DOI":"10.1007\/s13300-017-0295-y","article-title":"Diabetic neuropathy and gait: A review","volume":"8","author":"Alam","year":"2017","journal-title":"Diabetes Ther."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1705","DOI":"10.1016\/j.jbiomech.2016.03.056","article-title":"Gait ground reaction force characteristics of low back pain patients with pronated foot and able-bodied individuals with and without foot pronation","volume":"49","author":"Farahpour","year":"2016","journal-title":"J. Biomech."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1089\/dia.2014.0284","article-title":"Alterations in the lower limb joint moments precede the peripheral neuropathy diagnosis in diabetes patients","volume":"17","author":"Sacco","year":"2015","journal-title":"Diabetes Technol. Ther."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"738","DOI":"10.1016\/j.media.2011.05.016","article-title":"Automatic analysis of diabetic peripheral neuropathy using multi-scale quantitative morphology of nerve fibres in corneal confocal microscopy imaging","volume":"15","author":"Dabbah","year":"2011","journal-title":"Med. Image Anal."},{"key":"ref_17","unstructured":"(2020, February 09). International Diabetes Federation: IDF Diabetes Atlas. Available online: https:\/\/www.idf.org\/e-library\/epidemiology-research\/diabetes-atlas\/19-atlas-6th-edition.html."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1016\/j.jpain.2009.08.005","article-title":"Impact of postherpetic neuralgia and painful diabetic peripheral neuropathy on health care costs","volume":"11","author":"Dworkin","year":"2010","journal-title":"J. Pain"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1002\/mus.21661","article-title":"Signs and symptoms versus nerve conduction studies to diagnose diabetic sensorimotor polyneuropathy: Cl vs. NPhys trial","volume":"42","author":"Dyck","year":"2010","journal-title":"Muscle Nerve"},{"key":"ref_20","first-page":"21","article-title":"The diagnostic sensitivity, specificity and reproducibility of the clinical physical examination signs in patients of diabetes mellitus for making diagnosis of peripheral neuropathy","volume":"1","author":"Taksande","year":"2011","journal-title":"J. Endocrinol. Metab."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1186\/1743-0003-11-11","article-title":"Effect of diabetic neuropathy severity classified by a fuzzy model in muscle dynamics during gait","volume":"11","author":"Watari","year":"2014","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1212\/01.wnl.0000336370.51010.a1","article-title":"Practice Parameter: Evaluation of distal symmetric polyneuropathy: Role of laboratory and genetic testing (an evidence-based review) Report of the American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Academy of Physical Medicine and Rehabilitation","volume":"72","author":"England","year":"2009","journal-title":"Neurology"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"100298","DOI":"10.1016\/j.sbsr.2019.100298","article-title":"A low-cost and highly integrated sensing insole for plantar pressure measurement","volume":"26","author":"Zhang","year":"2019","journal-title":"Sens. Bio-Sens. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1001","DOI":"10.1016\/j.jallcom.2019.01.294","article-title":"Ultrasensitive and wearable strain sensors based on natural rubber\/graphene foam","volume":"785","author":"Zhang","year":"2019","journal-title":"J. Alloys Compd."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"35201","DOI":"10.1021\/acsami.9b11776","article-title":"Ultralightweight and 3D Squeezable Graphene-Polydimethylsiloxane Composite Foams as Piezoresistive Sensors","volume":"11","author":"Sengupta","year":"2019","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1109\/TITB.2009.2038904","article-title":"In-shoe plantar pressure measurement and analysis system based on fabric pressure sensing array","volume":"14","author":"Shu","year":"2010","journal-title":"IEEE Trans. Inf. Technol. Biomed."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Giovanelli, D., and Farella, E. (2016). Force sensing resistor and evaluation of technology for wearable body pressure sensing. J. Sens., 2016.","DOI":"10.1155\/2016\/9391850"},{"key":"ref_28","unstructured":"(2020, February 09). Feasibility of Force Detection in 3D Printed Flexible Material Using Embedded Sensors. Available online: https:\/\/www.spiedigitallibrary.org\/conference-proceedings-of-spie\/10970\/109702F\/Feasibility-of-force-detection-in-3D-printed-flexible-material-using\/10.1117\/12.2514051.short?SSO=1."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Heng, W., Pang, G., Xu, F., Huang, X., Pang, Z., and Yang, G. (2019). Flexible Insole Sensors with Stably Connected Electrodes for Gait Phase Detection. Sensors, 19.","DOI":"10.3390\/s19235197"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Lee, W., Hong, S.-H., and Oh, H.-W. (2019). Characterization of Elastic Polymer-Based Smart Insole and a Simple Foot Plantar Pressure Visualization Method Using 16 Electrodes. Sensors, 19.","DOI":"10.3390\/s19010044"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"102079","DOI":"10.1016\/j.yofte.2019.102079","article-title":"Recent trends and advances of fibre Bragg grating sensors in CYTOP polymer optical fibres","volume":"54","author":"Theodosiou","year":"2020","journal-title":"Opt. Fiber Technol."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Abdelhady, M., van den Bogert, A., and Simon, D. (2019). A High-Fidelity Wearable System for Measuring Lower-Limb Kinetics and Kinematics. IEEE Sens. J.","DOI":"10.1109\/JSEN.2019.2940517"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Kim, J., Bae, M.N., Lee, K.B., and Hong, S.G. (2019). Gait event detection algorithm based on smart insoles. ETRI J.","DOI":"10.4218\/etrij.2018-0639"},{"key":"ref_34","unstructured":"Vilas-Boas, M.d.C., Rocha, A.P., Choupina, H.M.P., Cardoso, M., Fernandes, J.M., Coelho, T., and Cunha, J.P.S. (2019, January 23\u201327). TTR-FAP Progression Evaluation Based on Gait Analysis Using a Single RGB-D Camera. Proceedings of the 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Berlin, Germany."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Cui, X., Zhao, Z., Ma, C., Chen, F., and Liao, H. (2018, January 3\u20138). A Gait Character Analyzing System for Osteoarthritis Pre-diagnosis Using RGB-D Camera and Supervised Classifier. Proceedings of the World Congress on Medical Physics and Biomedical Engineering, Prague, Czech Republic.","DOI":"10.1007\/978-981-10-9035-6_53"},{"key":"ref_36","first-page":"18","article-title":"Force Sensitive Resistors Calibration for the Usage in Gripping Devices","volume":"3","author":"Barnea","year":"2012","journal-title":"Diagn. Predict. Mech. Eng. Szstems DIPRE"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Parmar, S., Khodasevych, I., and Troynikov, O. (2017). Evaluation of flexible force sensors for pressure monitoring in treatment of chronic venous disorders. Sensors, 17.","DOI":"10.3390\/s17081923"},{"key":"ref_38","unstructured":"(2020, February 09). Insole Energy Harvesting from Human Movement Using Piezoelectric Generators. Available online: https:\/\/trepo.tuni.fi\/handle\/123456789\/25768."},{"key":"ref_39","unstructured":"(2020, February 09). Development of a Smart Insole System for Real-Time Detection of Temporal Gait Parameters and Related Deviations in Unilateral Lower-Limb Amputees. Available online: https:\/\/scholarlyrepository.miami.edu\/cgi\/viewcontent.cgi?article=1393&context=oa_theses."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"196","DOI":"10.1016\/S0268-0033(99)00060-1","article-title":"A study of biomechanical parameters in gait analysis and sensitive cronaxie of diabetic neuropathic patients","volume":"15","author":"Sacco","year":"2000","journal-title":"Clin. Biomech."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.apmr.2003.06.015","article-title":"Walking stability and sensorimotor function in older people with diabetic peripheral neuropathy1","volume":"85","author":"Menz","year":"2004","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Dementyev, A., Hodges, S., Taylor, S., and Smith, J. (2013, January 14\u201318). Power consumption analysis of Bluetooth Low Energy, ZigBee and ANT sensor nodes in a cyclic sleep scenario. Proceedings of the 2013 IEEE International Wireless Symposium (IWS), Beijing, China.","DOI":"10.1109\/IEEE-IWS.2013.6616827"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1016\/S0268-0033(03)00043-3","article-title":"Influence of the diabetic neuropathy on the behavior of electromyographic and sensorial responses in treadmill gait","volume":"18","author":"Sacco","year":"2003","journal-title":"Clin. Biomech."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/S0966-6362(02)00166-2","article-title":"Comparison of muscle activity during walking in subjects with and without diabetic neuropathy","volume":"18","author":"Kwon","year":"2003","journal-title":"Gait Posture"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"584","DOI":"10.1016\/j.clinbiomech.2007.11.015","article-title":"The effect of diabetic neuropathy and previous foot ulceration in EMG and ground reaction forces during gait","volume":"23","author":"Akashi","year":"2008","journal-title":"Clin. Biomech."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Sacco, I.C., Akashi, P.M., and Hennig, E.M. (2010). A comparison of lower limb EMG and ground reaction forces between barefoot and shod gait in participants with diabetic neuropathic and healthy controls. BMC Musculoskelet. Disord., 11.","DOI":"10.1186\/1471-2474-11-24"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1002\/mus.22051","article-title":"Electromyography and kinematic changes of gait cycle at different cadences in diabetic neuropathic individuals","volume":"44","author":"Gomes","year":"2011","journal-title":"Muscle Nerve"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.gaitpost.2011.08.016","article-title":"Abnormal muscle activation during gait in diabetes patients with and without neuropathy","volume":"35","author":"Sawacha","year":"2012","journal-title":"Gait Posture"},{"key":"ref_49","first-page":"390","article-title":"Foot pressure distribution during walking and shuffling","volume":"72","author":"Zhu","year":"1991","journal-title":"Arch. Phys. Med. Rehabil."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/4\/957\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:56:42Z","timestamp":1760173002000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/4\/957"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,11]]},"references-count":49,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["s20040957"],"URL":"https:\/\/doi.org\/10.3390\/s20040957","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,11]]}}}