Accuracy and Precision of a Novel Photogate System to Measure Toe Clearance on Stairs


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 ± 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’s correlation coefficient compared the accuracy, precision and relationship between systems. Results: We found a mean difference of −1.5 mm (accuracy) between the two measurement systems, with upper and lower limits (precision) of 10.7 mm and −13.8 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.

Publication DOI:
Divisions: College of Health & Life Sciences > School of Psychology
College of Health & Life Sciences > Aston Institute of Health & Neurodevelopment (AIHN)
College of Health & Life Sciences
Additional Information: Copyright © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( Funding: This research was funded by a Liverpool John Moores University (UK) PhD scholarship.
Uncontrolled Keywords: optoelectronic,photogates,stair safety,toe clearance,Analytical Chemistry,Information Systems,Biochemistry,Atomic and Molecular Physics, and Optics,Instrumentation,Electrical and Electronic Engineering
Publication ISSN: 1424-8220
Last Modified: 20 Jun 2024 07:23
Date Deposited: 06 Mar 2023 13:44
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Related URLs: https://www.mdp ... -8220/23/5/2429 (Publisher URL)
http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2023-03
Published Online Date: 2023-02-22
Accepted Date: 2023-02-12
Authors: Skervin, Timmion K.
Thomas, Neil M.
Schofield, Andrew J. (ORCID Profile 0000-0002-0589-4678)
Hollands, Mark A.
Maganaris, Constantinos N.
O’Brien, Thomas D.
Baltzopoulos, Vasilios
Foster, Richard J.



Version: Published Version

License: Creative Commons Attribution

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