{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,21]],"date-time":"2026-04-21T15:09:21Z","timestamp":1776784161825,"version":"3.51.2"},"reference-count":54,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2023,5,11]],"date-time":"2023-05-11T00:00:00Z","timestamp":1683763200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Presbyterian Health Foundation (PHF)","award":["R23-03"],"award-info":[{"award-number":["R23-03"]}]},{"name":"Presbyterian Health Foundation (PHF)","award":["P30CA225520"],"award-info":[{"award-number":["P30CA225520"]}]},{"name":"New Investigator Seed Grant Award to Elizabeth Hile","award":["R23-03"],"award-info":[{"award-number":["R23-03"]}]},{"name":"New Investigator Seed Grant Award to Elizabeth Hile","award":["P30CA225520"],"award-info":[{"award-number":["P30CA225520"]}]},{"name":"Oklahoma Tobacco Settlement Endowment Trust (TSET)","award":["R23-03"],"award-info":[{"award-number":["R23-03"]}]},{"name":"Oklahoma Tobacco Settlement Endowment Trust (TSET)","award":["P30CA225520"],"award-info":[{"award-number":["P30CA225520"]}]},{"name":"National Cancer Institute Cancer Center","award":["R23-03"],"award-info":[{"award-number":["R23-03"]}]},{"name":"National Cancer Institute Cancer Center","award":["P30CA225520"],"award-info":[{"award-number":["P30CA225520"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Hallux strength is associated with sports performance and balance across the lifespan, and independently predicts falls in older adults. In rehabilitation, Medical Research Council (MRC) Manual Muscle Testing (MMT) is the clinical standard for hallux strength assessment, but subtle weakness and longitudinal changes in strength may go undetected. To address the need for research-grade yet clinically feasible options, we designed a new load cell device and testing protocol to Quantify Hallux Extension strength (QuHalEx). We aim to describe the device, protocol and initial validation. In benchtop testing, we used eight precision weights to apply known loads from 9.81 to 78.5 N. In healthy adults, we performed three maximal isometric tests for hallux extension and flexion on the right and left sides. We calculated the Intraclass Correlation Coefficient (ICC) with 95% confidence interval and descriptively compared our isometric force\u2013time output to published parameters. QuHalEx benchtop absolute error ranged from 0.02 to 0.41 (mean 0.14) N. Benchtop and human intrasession output was repeatable (ICC 0.90\u20131.00, p &lt; 0.001). Hallux strength in our sample (n = 38, age 33.5 \u00b1 9.6 years, 53% female, 55% white) ranged from 23.1 to 82.0 N peak extension force and 32.0 to 142.4 N peak flexion, and differences of ~10 N (15%) between toes of the same MRC grade (5) suggest that QuHalEx is able to detect subtle weakness and interlimb asymmetries that are missed by MMT. Our results support ongoing QuHalEx validation and device refinement with a longer-term goal of widespread clinical and research application.<\/jats:p>","DOI":"10.3390\/s23104654","type":"journal-article","created":{"date-parts":[[2023,5,11]],"date-time":"2023-05-11T04:29:01Z","timestamp":1683779341000},"page":"4654","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Development and Earliest Validation of a Portable Device for Quantification of Hallux Extension Strength (QuHalEx)"],"prefix":"10.3390","volume":"23","author":[{"given":"Elizabeth S.","family":"Hile","sequence":"first","affiliation":[{"name":"Department of Rehabilitation Sciences, University of Oklahoma Health Sciences Center College of Allied Health, 1200 North Stonewall Ave., Oklahoma City, OK 73117, USA"},{"name":"OU Health Stephenson Cancer Center, 800 NE 10th Street, Oklahoma City, OK 73104, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mustafa","family":"Ghazi","sequence":"additional","affiliation":[{"name":"Infant Neuromotor Control Laboratory, Division of Developmental-Behavioral Pediatrics, Children\u2019s Hospital Los Angeles, Los Angeles, CA 90027, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Raghuveer","family":"Chandrashekhar","sequence":"additional","affiliation":[{"name":"Department of Occupational Therapy, University of Florida, Gainesville, FL 32603, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Josiah","family":"Rippetoe","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation Sciences, University of Oklahoma Health Sciences Center College of Allied Health, 1200 North Stonewall Ave., Oklahoma City, OK 73117, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ashley","family":"Fox","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation Sciences, University of Oklahoma Health Sciences Center College of Allied Health, 1200 North Stonewall Ave., Oklahoma City, OK 73117, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6567-9144","authenticated-orcid":false,"given":"Hongwu","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Occupational Therapy, University of Florida, Gainesville, FL 32603, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"109719","DOI":"10.1016\/j.jbiomech.2020.109719","article-title":"Importance of toe flexor strength in vertical jump performance","volume":"104","author":"Yamauchi","year":"2020","journal-title":"J. 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