{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:24:23Z","timestamp":1760239463691,"version":"build-2065373602"},"reference-count":48,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2020,11,20]],"date-time":"2020-11-20T00:00:00Z","timestamp":1605830400000},"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>Gait abnormalities such as high stride and step frequency\/cadence (SF\u2014stride\/second, CAD\u2014step\/second), stride variability (SV) and low harmony may increase the risk of injuries and be a sentinel of medical conditions. This research aims to present a new markerless video-based technology for quantitative and qualitative gait analysis. 86 healthy individuals (mead age 32 years) performed a 90 s test on treadmill at self-selected walking speed. We measured SF and CAD by a photoelectric sensors system; then, we calculated average \u00b1 standard deviation (SD) and within-subject coefficient of variation (CV) of SF as an index of SV. We also recorded a 60 fps video of the patient. With a custom-designed web-based video analysis software, we performed a spectral analysis of the brightness over time for each pixel of the image, that reinstituted the frequency contents of the videos. The two main frequency contents (F1 and F2) from this analysis should reflect the forcing\/dominant variables, i.e., SF and CAD. Then, a harmony index (HI) was calculated, that should reflect the proportion of the pixels of the image that move consistently with F1 or its supraharmonics. The higher the HI value, the less variable the gait. The correspondence SF-F1 and CAD-F2 was evaluated with both paired t-Test and correlation and the relationship between SV and HI with correlation. SF and CAD were not significantly different from and highly correlated with F1 (0.893 \u00b1 0.080 Hz vs. 0.895 \u00b1 0.084 Hz, p &lt; 0.001, r2 = 0.99) and F2 (1.787 \u00b1 0.163 Hz vs. 1.791 \u00b1 0.165 Hz, p &lt; 0.001, r2 = 0.97). The SV was 1.84% \u00b1 0.66% and it was significantly and moderately correlated with HI (0.082 \u00b1 0.028, p &lt; 0.001, r2 = 0.13). The innovative video-based technique of global, markerless gait analysis proposed in our study accurately identifies the main frequency contents and the variability of gait in healthy individuals, thus providing a time-efficient, low-cost means to quantitatively and qualitatively study human locomotion.<\/jats:p>","DOI":"10.3390\/s20226654","type":"journal-article","created":{"date-parts":[[2020,11,23]],"date-time":"2020-11-23T01:28:48Z","timestamp":1606094928000},"page":"6654","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Testing the Performance of an Innovative Markerless Technique for Quantitative and Qualitative Gait Analysis"],"prefix":"10.3390","volume":"20","author":[{"given":"Laura","family":"Simoni","sequence":"first","affiliation":[{"name":"Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37129 Verona, Italy"},{"name":"IRCCS Fondazione Don Carlo Gnocchi ONLUS, 50143 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alessandra","family":"Scarton","sequence":"additional","affiliation":[{"name":"Microgate SRL, 39100 Bolzano, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Filippo","family":"Gerli","sequence":"additional","affiliation":[{"name":"IRCCS Fondazione Don Carlo Gnocchi ONLUS, 50143 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Claudio","family":"Macchi","sequence":"additional","affiliation":[{"name":"IRCCS Fondazione Don Carlo Gnocchi ONLUS, 50143 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Federico","family":"Gori","sequence":"additional","affiliation":[{"name":"Microgate SRL, 39100 Bolzano, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Guido","family":"Pasquini","sequence":"additional","affiliation":[{"name":"IRCCS Fondazione Don Carlo Gnocchi ONLUS, 50143 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Silvia","family":"Pogliaghi","sequence":"additional","affiliation":[{"name":"Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37129 Verona, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,20]]},"reference":[{"key":"ref_1","unstructured":"WHO (2001). International Classification of Functioning, Disability and Health, World Health Organization."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/j.cmpb.2012.02.003","article-title":"Estimation of spatial-temporal gait parameters in level walking based on a single accelerometer: Validation on normal subjects by standard gait analysis","volume":"108","author":"Benedetti","year":"2012","journal-title":"Comput. Methods Programs Biomed."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.gaitpost.2011.03.027","article-title":"Efficacy of clinical gait analysis: A systematic review","volume":"34","author":"Wren","year":"2011","journal-title":"Gait Posture"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"347","DOI":"10.1016\/j.csm.2010.03.013","article-title":"Kinematics and kinetics of gait: From lab to clinic","volume":"29","author":"Dicharry","year":"2010","journal-title":"Clin. Sports Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"558","DOI":"10.1016\/j.gaitpost.2011.06.018","article-title":"Assessment of spatio-temporal gait parameters using inertial measurement units in neurological populations","volume":"34","author":"Esser","year":"2011","journal-title":"Gait Posture"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1575","DOI":"10.3109\/02699052.2010.523053","article-title":"Temporospatial characteristics of gait in patients with lower limb muscle hypertonia after traumatic brain injury","volume":"24","author":"Chow","year":"2010","journal-title":"Brain Inj."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"407","DOI":"10.1016\/j.ocl.2009.02.004","article-title":"Spatiotemporal parameters of gait after total hip replacement: Anterior versus posterior approach","volume":"40","author":"Maffiuletti","year":"2009","journal-title":"Orthop. Clin. N. Am."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"897","DOI":"10.1016\/j.burns.2019.10.022","article-title":"Evaluation of spatio-temporal gait parameters and gait symmetry in diabetic polyneuropathic patients with burn injury: A pilot study","volume":"46","author":"Erdem","year":"2020","journal-title":"Burn"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"961","DOI":"10.1016\/j.nmd.2019.11.003","article-title":"GNE myopathy\u2014A cross-sectional study on spatio-temporal gait characteristics","volume":"29","author":"Gomez","year":"2019","journal-title":"Neuromuscul. Disord."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1155\/2013\/918642","article-title":"The golden ratio of gait harmony: Repetitive proportions of repetitive gait phases","volume":"2013","author":"Iosa","year":"2013","journal-title":"BioMed Res. Int."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1540","DOI":"10.1016\/j.clinph.2015.11.016","article-title":"Loss of fractal gait harmony in Parkinson\u2019s Disease","volume":"127","author":"Iosa","year":"2016","journal-title":"Clin. Neurophysiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"138","DOI":"10.1016\/j.neulet.2015.12.023","article-title":"The connection between anthropometry and gait harmony unveiled through the lens of the golden ratio","volume":"612","author":"Iosa","year":"2016","journal-title":"Neurosci. Lett."},{"key":"ref_13","first-page":"M446","article-title":"Acceleration patterns of the head and pelvis when walking are associated with risk of falling in community-dwelling older people","volume":"58","author":"Menz","year":"2003","journal-title":"J. Gerontol. Ser. A Boil. Sci. Med. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"992","DOI":"10.1016\/j.jbiomech.2016.01.015","article-title":"Analysis of dual-task elderly gait in fallers and non-fallers using wearable sensors","volume":"49","author":"Howcroft","year":"2016","journal-title":"J. Biomech."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1768","DOI":"10.1080\/02640414.2017.1416974","article-title":"Coordination in gait: Demonstration of a spectral approach","volume":"36","author":"Williams","year":"2017","journal-title":"J. Sports Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"828","DOI":"10.1016\/j.jbiomech.2012.12.008","article-title":"Harmonic ratios: A quantification of step to step symmetry","volume":"46","author":"Bellanca","year":"2013","journal-title":"J. Biomech."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/j.clinbiomech.2017.07.001","article-title":"Harmony as a convergence attractor that minimizes the energy expenditure and variability in physiological gait and the loss of harmony in cerebellar ataxia","volume":"48","author":"Serrao","year":"2017","journal-title":"Clin. Biomech."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1055\/s-0033-1336016","article-title":"Ability and stability of running and walking in children with cerebral palsy","volume":"44","author":"Morelli","year":"2013","journal-title":"Neuropediatrics"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1682\/JRRD.2013.07.0162","article-title":"Assessment of gait stability, harmony, and symmetry in subjects with lower-limb amputation evaluated by trunk accelerations","volume":"51","author":"Iosa","year":"2014","journal-title":"J. Rehabil. Res. Dev."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.jbiomech.2017.01.005","article-title":"Overcoming the limitations of the Harmonic Ratio for the reliable assessment of gait symmetry","volume":"53","author":"Pasciuto","year":"2017","journal-title":"J. Biomech."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1016\/j.gaitpost.2016.11.005","article-title":"Asymmetry between lower limbs during rested and fatigued state running gait in healthy individuals","volume":"51","author":"Radzak","year":"2017","journal-title":"Gait Posture"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1123\/jab.2015-0266","article-title":"Associations between step duration variability and inertial measurement unit derived gait characteristics","volume":"32","author":"Rantalainen","year":"2016","journal-title":"J. Appl. Biomech."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"265","DOI":"10.23736\/S1973-9087.18.05306-6","article-title":"Inertial sensors versus standard systems in gait analysis: A systematic review and meta-analysis","volume":"55","author":"Petraglia","year":"2019","journal-title":"Eur. J. Phys. Rehabil. Med."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s40798-018-0139-y","article-title":"A review of the evolution of vision-based motion analysis and the integration of advanced computer vision methods towards developing a markerless system","volume":"4","author":"Colyer","year":"2018","journal-title":"Sports Med.-Open"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/j.jbiomech.2019.06.017","article-title":"\u00c1ngel; Ram\u00edrez-Campillo, R.; Roche-Seruendo, L.E. Agreement between spatiotemporal parameters from a photoelectric system with different filter settings and high-speed video analysis during running on a treadmill at comfortable velocity","volume":"93","year":"2019","journal-title":"J. Biomech."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1002\/mds.22352","article-title":"Walking stability using harmonic ratios in Parkinson\u2019s disease","volume":"24","author":"Lowry","year":"2009","journal-title":"Mov. Disord. Off. J. Mov. Disord. Soc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3362","DOI":"10.3390\/s140203362","article-title":"Gait analysis methods: An overview of wearable and non-wearable systems, highlighting clinical applications","volume":"14","year":"2014","journal-title":"Sensors"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Verlekar, T.T., Soares, L.D., and Correia, P.L. (2018). Automatic classification of gait impairments using a markerless 2d video-based system. Sensors, 18.","DOI":"10.3390\/s18092743"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4605","DOI":"10.3390\/s150304605","article-title":"New lower-limb gait asymmetry indices based on a depth camera","volume":"15","author":"Auvinet","year":"2015","journal-title":"Sensors"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Zhang, A., Yang, S., Zhang, X., Zhang, J., and Zhang, W. (2017). Abnormal Gait Detection in Surveillance Videos with FFT-Based Analysis on Walking Rhythm. International Conference on Image and Graphics, Springer.","DOI":"10.1007\/978-3-319-71607-7_10"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1080\/00140138108924874","article-title":"A kinematic study of long-term habituation to treadmill walking","volume":"24","author":"Wall","year":"1981","journal-title":"Ergonomics"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41598-019-41721-0","article-title":"Familiarization with treadmill walking: How much is enough?","volume":"9","author":"Meyer","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1589\/jpts.26.81","article-title":"Concurrent validity and test-retest reliability of the OPTOGait photoelectric cell system for the assessment of spatio-temporal parameters of the gait of young adults","volume":"26","author":"Lee","year":"2014","journal-title":"J. Phys. Ther. Sci."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1177\/0269215518804294","article-title":"The mental representation of the human gait in hip osteoarthrosis and total hip arthroplasty patients: A clinical cross-sectional study","volume":"33","author":"Jacksteit","year":"2018","journal-title":"Clin. Rehabil."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/j.gaitpost.2019.03.031","article-title":"\u00c1lvarez; Gijon-Nogueron, G.; Asencio, J.M. The influence of childhood obesity on spatio-temporal gait parameters","volume":"71","author":"Alguacil","year":"2019","journal-title":"Gait Posture"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"02NT02","DOI":"10.1088\/1361-6579\/aaa74d","article-title":"Prediction of sustained harmonic walking in the free-living environment using raw accelerometry data","volume":"39","author":"Urbanek","year":"2018","journal-title":"Physiol. Meas."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1186\/1743-0003-11-131","article-title":"Measures of gait stability: Performance on adults and toddlers at the beginning of independent walking","volume":"11","author":"Bisi","year":"2014","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"10","DOI":"10.2352\/ISSN.2169-4672.2007.1.0.10","article-title":"Brightness calculation in digital image processing","volume":"2007","author":"Bezryadin","year":"2007","journal-title":"Int. Symp. Technol. Digit. Photo Fulfillment"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"MadehKhaksar, F., Klenk, J., Sczuka, K., Gordt, K., Melzer, I., and Schwenk, M. (2018). The effects of unexpected mechanical perturbations during treadmill walking on spatiotemporal gait parameters, and the dynamic stability measures by which to quantify postural response. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0195902"},{"key":"ref_40","first-page":"99","article-title":"Sex difference in the pattern of lower limb movement during treadmill walking","volume":"62","author":"Yamasaki","year":"1991","journal-title":"Graefe\u2019s Arch. Clin. Exp. Ophthalmol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.neucli.2008.02.002","article-title":"Effect of speed on kinematic, kinetic, electromyographic and energetic reference values during treadmill walking","volume":"38","author":"Stoquart","year":"2008","journal-title":"Neurophysiol. Clin. Neurophysiol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s12984-016-0115-z","article-title":"Validity and reliability of a portable gait analysis system for measuring spatiotemporal gait characteristics: Comparison to an instrumented treadmill","volume":"13","author":"Donath","year":"2016","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2722","DOI":"10.1016\/j.jbiomech.2013.08.011","article-title":"Concurrent validity of the Microsoft Kinect for assessment of spatiotemporal gait variables","volume":"46","author":"Clark","year":"2013","journal-title":"J. Biomech."},{"key":"ref_44","unstructured":"Nixon, M., and Carter, J. (2004, January 19). Advances in automatic gait recognition. Proceedings of the Sixth IEEE International Conference on Automatic Face and Gesture Recognition, Seoul, Korea."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1007\/s11042-011-0786-1","article-title":"Automatic recognition of gait-related health problems in the elderly using machine learning","volume":"58","author":"Pogorelc","year":"2011","journal-title":"Multimed. Tools Appl."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2925","DOI":"10.1109\/TBME.2013.2266341","article-title":"Unobtrusive, continuous, in-home gait measurement using the Microsoft Kinect","volume":"60","author":"Stone","year":"2013","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/S0966-6362(03)00030-4","article-title":"Stride variability in human gait: The effect of stride frequency and stride length","volume":"18","author":"Danion","year":"2003","journal-title":"Gait Posture"},{"key":"ref_48","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"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/22\/6654\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:35:09Z","timestamp":1760178909000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/22\/6654"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,11,20]]},"references-count":48,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2020,11]]}},"alternative-id":["s20226654"],"URL":"https:\/\/doi.org\/10.3390\/s20226654","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2020,11,20]]}}}