{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:10:12Z","timestamp":1760123412519,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2023,2,22]],"date-time":"2023-02-22T00:00:00Z","timestamp":1677024000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"a Liverpool John Moores University (UK) PhD scholarship"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Background: Toe clearance on stairs is typically measured using optoelectronic systems, though these are often constrained to the laboratory, due to their complex setups. Here we measured stair toe clearance through a novel prototype photogate setup and compared this to optoelectronic measurements. Methods: Twelve participants (age 22 \u00b1 3 years) completed 25 stair ascent trials, each on a seven-step staircase. Toe clearance over the fifth step edge was measured using Vicon and the photogates. Twenty-two photogates were created in rows through laser diodes and phototransistors. The height of the lowest photogate broken at step-edge crossing was used to determine photogate toe clearance. A limits of agreement analysis and Pearson\u2019s correlation coefficient compared the accuracy, precision and relationship between systems. Results: We found a mean difference of \u22121.5 mm (accuracy) between the two measurement systems, with upper and lower limits (precision) of 10.7 mm and \u221213.8 mm, respectively. A strong positive correlation was also found (r = 70, n = 12, p = 0.009) between the systems. Discussion: The results suggest that photogates could be an option for measuring real-world stair toe clearances, where optoelectronic systems are not routinely used. Improvements to the design and measurement factors may help to improve the precision of the photogates.<\/jats:p>","DOI":"10.3390\/s23052429","type":"journal-article","created":{"date-parts":[[2023,2,23]],"date-time":"2023-02-23T02:01:25Z","timestamp":1677117685000},"page":"2429","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Accuracy and Precision of a Novel Photogate System to Measure Toe Clearance on Stairs"],"prefix":"10.3390","volume":"23","author":[{"given":"Timmion K.","family":"Skervin","sequence":"first","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Neil M.","family":"Thomas","sequence":"additional","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0589-4678","authenticated-orcid":false,"given":"Andrew J.","family":"Schofield","sequence":"additional","affiliation":[{"name":"School of Psychology & Aston Research Centre for Healthy Ageing, College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4043-1839","authenticated-orcid":false,"given":"Mark A.","family":"Hollands","sequence":"additional","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Constantinos N.","family":"Maganaris","sequence":"additional","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas D.","family":"O\u2019Brien","sequence":"additional","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vasilios","family":"Baltzopoulos","sequence":"additional","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Richard J.","family":"Foster","sequence":"additional","affiliation":[{"name":"Research to Improve Stair Climbing Safety (RISCS), Faculty of Science, School of Sport and Exercise Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/j.gaitpost.2016.06.030","article-title":"A review of stairway falls and stair negotiation: Lessons learned and future needs to reduce injury","volume":"49","author":"Jacobs","year":"2016","journal-title":"Gait Posture"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.gaitpost.2004.01.006","article-title":"Foot clearance during stair descent: Effects of age and illumination","volume":"21","author":"Hamel","year":"2005","journal-title":"Gait Posture"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2950","DOI":"10.1167\/iovs.14-16018","article-title":"What you see is what you step: The horizontal-vertical illusion increases toe clearance in older adults during stair ascent","volume":"56","author":"Foster","year":"2015","journal-title":"Investig. Ophthalmol. Vis. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.apergo.2015.05.011","article-title":"Analysis of foot clearance in firefighters during ascent and descent of stairs","volume":"52","author":"Kesler","year":"2016","journal-title":"Appl. Ergon."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"109820","DOI":"10.1016\/j.jbiomech.2020.109820","article-title":"A comparison of currently available optoelectronic motion capture systems","volume":"106","author":"Topley","year":"2020","journal-title":"J. Biomech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1400","DOI":"10.1016\/j.jbiomech.2013.02.013","article-title":"The detailed measurement of foot clearance by young adults during stair descent","volume":"46","author":"Telonio","year":"2013","journal-title":"J. Biomech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"110646","DOI":"10.1016\/j.exger.2019.110646","article-title":"A novel multivariate approach for biomechanical profiling of stair negotiation","volume":"124","author":"Ackermans","year":"2019","journal-title":"Exp. Gerontol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"103131","DOI":"10.1016\/j.apergo.2020.103131","article-title":"Negotiating stairs with an inconsistent riser: Implications for stepping safety","volume":"87","author":"Francksen","year":"2020","journal-title":"Appl. Ergon."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Benoussaad, M., Sijobert, B., Mombaur, K., and Coste, C.A. (2016). Robust foot clearance estimation based on the integration of foot-mounted IMU acceleration data. Sensors, 16.","DOI":"10.3390\/s16010012"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41598-019-54913-5","article-title":"A low-cost 2-D video system can accurately and reliably assess adaptive gait kinematics in healthy and low vision subjects","volume":"9","author":"Zult","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Selvaraj, M., Baltzopoulos, V., Shaw, A., Maganaris, C.N., Cullen, J., O\u2019Brien, T., and Kot, P. (2018, January 2\u20135). Stair fall risk detection using wearable sensors. Proceedings of the 2018 11th International Conference on Developments in eSystems Engineering (DeSE), Cambridge, UK.","DOI":"10.1109\/DeSE.2018.00023"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"111309","DOI":"10.1016\/j.exger.2021.111309","article-title":"The next step in optimising the stair horizontal-vertical illusion: Does a perception-action link exist in older adults?","volume":"149","author":"Skervin","year":"2021","journal-title":"Exp. Gerontol."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Skervin, T.K., Thomas, N.M., Schofield, A.J., Hollands, M.A., Maganaris, C.N., O\u2019Brien, T.D., Baltzopoulos, V., and Foster, R.J. (2021). Using a stair horizontal-vertical illusion to increase foot clearance over an inconsistently taller stair-riser. PLoS One, 16.","DOI":"10.1371\/journal.pone.0257159"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1062","DOI":"10.1519\/JSC.0000000000001566","article-title":"Comparison of Three Timing Systems: Reliability and Best Practice Recommendations in Timing Short-Duration Sprints","volume":"31","author":"Bond","year":"2017","journal-title":"J. Strength Cond. Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"012127","DOI":"10.1088\/1742-6596\/1144\/1\/012127","article-title":"Photogate sensor for compound physical pendulum experiments","volume":"1144","author":"Suchatpong","year":"2018","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Lu, M.-J., Zhong, W.-H., Liu, Y.-X., Miao, H.-Z., Li, Y.-C., and Ji, M.-H. (2016). Sample size for assessing agreement between two methods of measurement by Bland\u2014Altman method. Int. J. Biostat., 12.","DOI":"10.1515\/ijb-2015-0039"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"330","DOI":"10.1111\/j.1475-1313.2011.00851.x","article-title":"Statistical methods for conducting agreement (comparison of clinical tests) and precision (repeatability or reproducibility) studies in optometry and ophthalmology","volume":"31","author":"McAlinden","year":"2011","journal-title":"Ophthalmic Physiol. Opt."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1002\/pst.382","article-title":"Sample size calculation for an agreement study","volume":"9","author":"Liao","year":"2010","journal-title":"Pharm. Stat."},{"key":"ref_19","unstructured":"Bland, J.M. (2023, February 08). How Can I Decide the Sample Size for a Study of Agreement between Two Methods of Measurement?. Available online: http:\/\/www-users.york.ac.uk\/~mb55\/meas\/sizemeth.htm."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1080\/23335432.2015.1049296","article-title":"Selecting the number of trials in experimental biomechanics studies","volume":"2","author":"Forrester","year":"2015","journal-title":"Int. Biomech."},{"key":"ref_21","unstructured":"(2022, March 12). Broadcom BCM2835 Arm Peripherals. Available online: https:\/\/www.raspberrypi.org\/wp-content\/uploads\/2012\/02\/BCM2835-ARM-Peripherals.pdf."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/S0140-6736(86)90837-8","article-title":"Statistical methods for assessing agreement between two methods of clinical measurement","volume":"327","author":"Bland","year":"1986","journal-title":"Lancet"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"571","DOI":"10.1080\/10543400701329422","article-title":"Agreement between methods of measurement with multiple observations per individual","volume":"17","author":"Bland","year":"2007","journal-title":"J. Biopharm. Stat."},{"key":"ref_24","unstructured":"R Core Team (2020). R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing."},{"key":"ref_25","unstructured":"Lehnert, B. (2015). R Package Version 0.3.1, R Foundation for Statistical Computing. BlandAltmanLeh: Plots (Slightly Extended) Bland-Altman Plots."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Merriaux, P., Dupuis, Y., Boutteau, R., Vasseur, P., and Savatier, X. (2017). A study of vicon system positioning performance. Sensors, 17.","DOI":"10.3390\/s17071591"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/5\/2429\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:39:21Z","timestamp":1760121561000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/5\/2429"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,2,22]]},"references-count":26,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2023,3]]}},"alternative-id":["s23052429"],"URL":"https:\/\/doi.org\/10.3390\/s23052429","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2023,2,22]]}}}