{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T07:02:57Z","timestamp":1779951777602,"version":"3.53.1"},"reference-count":41,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T00:00:00Z","timestamp":1779926400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Pediatr."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Neuromuscular development is of importance for motor performance. The aim of this study was to evaluate the reliability of instrumented measurements of ankle resistance during passive movements and muscle strength in the lower leg in children.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A test-retest design was used with a 2-way mixed-effects model to calculate intraclass correlation coefficients (ICC). Eleven typically developing children (eight girls), aged 7\u201314 years, participated. Passive ankle resistance was assessed with the NeuroFlexor, which performed controlled passive movements over 40\u00b0 from plantarflexion to maximal dorsiflexion at slow and fast velocities. A biomechanical model decomposed measured passive ankle resistance (torque) into non-neural (stiffness coefficient) and maximal neural torque (neural resistance) components. Muscle strength was measured using a rig-fixed dynamometer during maximal isometric voluntary contractions of the plantarflexors and dorsiflexors. Testing was performed twice throughout the same day with a 2-hour interval.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>ICC (95% CI) between the two measurements were as follows: stiffness coefficient: 0.79 (0.13,0.94); maximal neural torque: 0.96 (0.86,0.99); maximal voluntary contraction of plantarflexors: 0.96 (0.86, 0.99); and dorsiflexors 0.96 (0.86, 0.99).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The NeuroFlexor and rig-fixed dynamometer showed good to excellent test-retest reliability for assessing passive ankle joint resistance and muscle strength in typically developing children. Further research is needed to explore their use in clinical populations.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fped.2026.1832116","type":"journal-article","created":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T06:19:15Z","timestamp":1779949155000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Good to excellent reliability of instrumented ankle passive resistance and strength measurements in children"],"prefix":"10.3389","volume":"14","author":[{"given":"Alexandra","family":"\u00c5hblom","sequence":"first","affiliation":[{"name":"Department of Women\u2019s and Children\u2019s Health, Division of Pediatric Neurology, Karolinska Institutet","place":["Stockholm, Sweden"]},{"name":"Theme Women\u2019s Health and Allied Health Professionals, Medical Unit Allied Health Professional, Karolinska University Hospital","place":["Stockholm, Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhihao","family":"Duan","sequence":"additional","affiliation":[{"name":"Department of Engineering Mechanics, KTH MoveAbility, Royal Institute of Technology","place":["Stockholm, Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antea","family":"Destro","sequence":"additional","affiliation":[{"name":"Department of Engineering Mechanics, KTH MoveAbility, Royal Institute of Technology","place":["Stockholm, Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eva","family":"Pont\u00e9n","sequence":"additional","affiliation":[{"name":"Department of Women\u2019s and Children\u2019s Health, Division of Pediatric Neurology, Karolinska Institutet","place":["Stockholm, Sweden"]},{"name":"Department of Pediatric Orthopedic Surgery and Pediatric Neurology, Astrid Lindgren Children\u2019s Hospital, Karolinska University Hospital","place":["Stockholm, Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cecilia","family":"Lidbeck","sequence":"additional","affiliation":[{"name":"Department of Women\u2019s and Children\u2019s Health, Division of Pediatric Neurology, Karolinska Institutet","place":["Stockholm, Sweden"]},{"name":"Department of Pediatric Orthopedic Surgery and Pediatric Neurology, Astrid Lindgren Children\u2019s Hospital, Karolinska University Hospital","place":["Stockholm, Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruoli","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Women\u2019s and Children\u2019s Health, Division of Pediatric Neurology, Karolinska Institutet","place":["Stockholm, Sweden"]},{"name":"Department of Engineering Mechanics, KTH MoveAbility, Royal Institute of Technology","place":["Stockholm, Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,28]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"580","DOI":"10.1017\/s0012162204000994","article-title":"Motor impairments in young children with cerebral palsy: relationship to gross motor function and everyday activities","volume":"46","author":"Ostensj\u00f8","year":"2004","journal-title":"Dev Med Child Neurol"},{"key":"B2","doi-asserted-by":"publisher","first-page":"981","DOI":"10.1111\/ene.13322","article-title":"European Consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch","volume":"24","author":"van den Noort","year":"2017","journal-title":"Eur J Neurol"},{"key":"B3","doi-asserted-by":"publisher","first-page":"855222","DOI":"10.3389\/fphys.2022.855222","article-title":"Instrumented strength assessment in typically developing children and children with a neural or neuromuscular disorder: a reliability, validity and responsiveness study","volume":"13","author":"Verreydt","year":"2022","journal-title":"Front Physiol"},{"key":"B4","doi-asserted-by":"publisher","first-page":"81","DOI":"10.1186\/1743-0003-10-81","article-title":"Differentiation between non-neural and neural contributors to ankle joint stiffness in cerebral palsy","volume":"10","author":"de Gooijer-van de Groep","year":"2013","journal-title":"J Neuroeng Rehabil"},{"key":"B5","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1136\/jnnp.2009.177071","article-title":"Stop using the Ashworth scale for the assessment of spasticity","volume":"81","author":"Fleuren","year":"2010","journal-title":"J Neurol Neurosurg Psychiatry"},{"key":"B6","doi-asserted-by":"publisher","first-page":"576","DOI":"10.23736\/s1973-9087.17.04796-7","article-title":"Inter- and intra-rater reliability of the modified ashworth scale: a systematic review and meta-analysis","volume":"54","author":"Meseguer-Henarejos","year":"2018","journal-title":"Eur J Phys Rehabil Med"},{"key":"B7","doi-asserted-by":"publisher","first-page":"617","DOI":"10.1177\/1545968311403494","article-title":"Validation of a new biomechanical model to measure muscle tone in spastic muscles","volume":"25","author":"Lindberg","year":"2011","journal-title":"Neurorehabil Neural Repair"},{"key":"B8","doi-asserted-by":"publisher","first-page":"16","DOI":"10.1186\/s12984-022-00996-7","article-title":"The diagnostic levels of evidence of instrumented devices for measuring viscoelastic joint properties and spasticity; a systematic review","volume":"19","author":"van der Velden","year":"2022","journal-title":"J Neuroeng Rehabil"},{"key":"B9","doi-asserted-by":"publisher","first-page":"jrm00356","DOI":"10.2340\/jrm.v54.2067","article-title":"Validity, intra-rater reliability and normative data of the neuroflexor\u2122 device to measure spasticity of the ankle plantar flexors after stroke","volume":"55","author":"Pennati","year":"2023","journal-title":"J Rehabil Med"},{"key":"B10","doi-asserted-by":"publisher","first-page":"730","DOI":"10.3389\/fneur.2019.00730","article-title":"Measurement properties of the NeuroFlexor device for quantifying neural and non-neural components of wrist hyper-resistance in chronic stroke","volume":"10","author":"Andringa","year":"2019","journal-title":"Front Neurol"},{"key":"B11","doi-asserted-by":"publisher","first-page":"147","DOI":"10.1097\/00003086-198305000-00021","article-title":"Energy generation and absorption at the ankle and knee during fast, natural, and slow cadences","volume":"175","author":"Winter","year":"1983","journal-title":"Clin Orthop Relat Res"},{"key":"B12","doi-asserted-by":"publisher","first-page":"3676","DOI":"10.1242\/jeb.140376","article-title":"A unified perspective on ankle push-off in human walking","volume":"219","author":"Zelik","year":"2016","journal-title":"J Exp Biol"},{"key":"B13","doi-asserted-by":"publisher","first-page":"1217009","DOI":"10.3389\/fspor.2023.1217009","article-title":"Neuromuscular control: from a biomechanist\u2019s perspective","volume":"5","author":"Mulla","year":"2023","journal-title":"Front Sports Act Living"},{"key":"B14","doi-asserted-by":"publisher","first-page":"414","DOI":"10.1097\/pep.0000000000000179","article-title":"Hand-held dynamometry isometric torque reference values for children and adolescents","volume":"27","author":"H\u00e9bert","year":"2015","journal-title":"Pediatr Phys Ther"},{"key":"B15","doi-asserted-by":"publisher","first-page":"e0226274","DOI":"10.1371\/journal.pone.0226274","article-title":"Reliability of isokinetic knee strength measurements in children: a systematic review and meta-analysis","volume":"14","author":"Mu\u00f1oz-Bermejo","year":"2019","journal-title":"PLoS One"},{"key":"B16","doi-asserted-by":"publisher","first-page":"1091","DOI":"10.1016\/j.apmr.2006.05.012","article-title":"Isometric muscle torque in children 5 to 15 years of age: normative data","volume":"87","author":"Eek","year":"2006","journal-title":"Arch Phys Med Rehabil"},{"key":"B17","doi-asserted-by":"publisher","first-page":"36","DOI":"10.1212\/wnl.0000000000003466","article-title":"Normative reference values for strength and flexibility of 1,000 children and adults","volume":"88","author":"McKay","year":"2017","journal-title":"Neurology"},{"key":"B18","doi-asserted-by":"publisher","first-page":"160","DOI":"10.1123\/jsr.17.2.160","article-title":"Hand-held dynamometry: reliability of lower extremity muscle testing in healthy, physically active,young adults","volume":"17","author":"Kelln","year":"2008","journal-title":"J Sport Rehabil"},{"key":"B19","doi-asserted-by":"publisher","first-page":"191","DOI":"10.2519\/jospt.1991.13.4.191","article-title":"Hand-held dynamometer measurements: tester strength makes a difference","volume":"13","author":"Wikholm","year":"1991","journal-title":"J Orthop Sports Phys Ther"},{"key":"B20","first-page":"1","article-title":"A simplified guide to determination of sample size requirements for estimating the value of intraclass correlation coefficient: a review","volume":"12","author":"Bujang","year":"2017","journal-title":"Arch Orofac Sci"},{"key":"B21","doi-asserted-by":"publisher","first-page":"346","DOI":"10.1016\/j.gaitpost.2014.04.207","article-title":"Identification of the neural component of torque during manually-applied spasticity assessments in children with cerebral palsy","volume":"40","author":"Bar-On","year":"2014","journal-title":"Gait Posture"},{"key":"B22","doi-asserted-by":"publisher","first-page":"73","DOI":"10.3389\/fbioe.2018.00073","article-title":"Changes in the neural and non-neural related properties of the spastic wrist flexors after treatment with Botulinum toxin A in post-stroke subjects: an optimization study","volume":"6","author":"Wang","year":"2018","journal-title":"Front Bioeng Biotechnol"},{"key":"B23","doi-asserted-by":"publisher","first-page":"198","DOI":"10.1016\/j.medengphy.2017.06.023","article-title":"Neural and non-neural related properties in the spastic wrist flexors: an optimization study","volume":"47","author":"Wang","year":"2017","journal-title":"Med Eng Phys"},{"key":"B24","doi-asserted-by":"publisher","first-page":"803","DOI":"10.1186\/s12891-024-07890-4","article-title":"Exploration of the triceps surae muscle in ambulatory children with cerebral palsy using instrumented measurements of stiffness and diffusion tensor magnetic resonance imaging for muscle architecture","volume":"25","author":"\u00c5hblom","year":"2024","journal-title":"BMC Musculoskelet Disord"},{"key":"B25","doi-asserted-by":"publisher","first-page":"3105","DOI":"10.1016\/j.jbiomech.2007.03.022","article-title":"Maximum voluntary joint torque as a function of joint angle and angular velocity: model development and application to the lower limb","volume":"40","author":"Anderson","year":"2007","journal-title":"J Biomech"},{"key":"B26","doi-asserted-by":"publisher","first-page":"68","DOI":"10.1017\/s0012162201001682","article-title":"Should we be testing and training muscle strength in cerebral palsy?","volume":"44","author":"Damiano","year":"2002","journal-title":"Dev Med Child Neurol"},{"key":"B27","doi-asserted-by":"crossref","DOI":"10.1017\/CBO9780511996214","volume-title":"Measurement in Medicine: A Practical Guide","author":"de Vet","year":"2011"},{"key":"B28","doi-asserted-by":"publisher","first-page":"155","DOI":"10.1016\/j.jcm.2016.02.012","article-title":"A guideline of selecting and reporting intraclass correlation coefficients for reliability research","volume":"15","author":"Koo","year":"2016","journal-title":"J Chiropr Med"},{"key":"B29","doi-asserted-by":"publisher","first-page":"135","DOI":"10.3109\/09638288.2015.1095950","article-title":"Isometric muscle strength and mobility capacity in children with cerebral palsy","volume":"39","author":"Dallmeijer","year":"2017","journal-title":"Disabil Rehabil"},{"key":"B30","doi-asserted-by":"publisher","first-page":"289","DOI":"10.1097\/PEP.0b013e318227ccff","article-title":"Isometric muscle strength in youth assessed by hand-held dynamometry: a feasibility, reliability, and validity study","volume":"23","author":"H\u00e9bert","year":"2011","journal-title":"Pediatr Phys Ther"},{"key":"B31","doi-asserted-by":"publisher","first-page":"188","DOI":"10.1186\/s12883-015-0441-y","article-title":"Muscle strength does not explain standing ability in children with bilateral spastic cerebral palsy: a cross sectional descriptive study","volume":"15","author":"Lidbeck","year":"2015","journal-title":"BMC Neurol"},{"key":"B32","first-page":"820","article-title":"The validity of plantarflexor strength measures obtained through hand-held dynamometry measurements of force","volume":"8","author":"Marmon","year":"2013","journal-title":"Int J Sports Phys Ther"},{"key":"B33","doi-asserted-by":"publisher","first-page":"542","DOI":"10.1017\/s0012162203000999","article-title":"Contributing factors to muscle weakness in children with cerebral palsy","volume":"45","author":"Elder","year":"2003","journal-title":"Dev Med Child Neurol"},{"key":"B34","doi-asserted-by":"publisher","first-page":"163","DOI":"10.29011\/2576-9596.100063","article-title":"Gastrocnemius and soleus muscle contributions to ankle plantar flexion torque as a function of ankle and knee angle","volume":"4","author":"Ferris","year":"2020","journal-title":"Sports Injr Med"},{"key":"B35","doi-asserted-by":"publisher","first-page":"253","DOI":"10.26603\/001c.128591","article-title":"Excellent reliability for an instrumented test of ankle plantarflexion force","volume":"20","author":"Glaied","year":"2025","journal-title":"Int J Sports Phys Ther"},{"key":"B36","doi-asserted-by":"publisher","first-page":"326","DOI":"10.1016\/j.gaitpost.2010.10.092","article-title":"Association between isometric muscle strength and gait joint kinetics in adolescents and young adults with cerebral palsy","volume":"33","author":"Dallmeijer","year":"2011","journal-title":"Gait Posture"},{"key":"B37","doi-asserted-by":"publisher","first-page":"366","DOI":"10.1016\/j.gaitpost.2008.05.004","article-title":"Walking ability is related to muscle strength in children with cerebral palsy","volume":"28","author":"Eek","year":"2008","journal-title":"Gait Posture"},{"key":"B38","doi-asserted-by":"publisher","first-page":"1446","DOI":"10.1016\/j.apmr.2007.06.775","article-title":"Normalizing lower-extremity strength data for children without disability using allometric scaling","volume":"88","author":"Wren","year":"2007","journal-title":"Arch Phys Med Rehabil"},{"key":"B39","doi-asserted-by":"publisher","first-page":"224","DOI":"10.3109\/21679169.2015.1081278","article-title":"Muscle weakness does not influence gait in unilateral cerebral palsy: a muscle strength and three-dimensional gait analysis study","volume":"17","author":"Riad","year":"2015","journal-title":"Eur J Physiother"},{"key":"B40","doi-asserted-by":"publisher","first-page":"68","DOI":"10.1111\/j.1469-8749.2010.03777.x","article-title":"Causal relation between spasticity, strength, gross motor function, and functional outcome in children with cerebral palsy: a path analysis","volume":"53","author":"Kim","year":"2011","journal-title":"Dev Med Child Neurol"},{"key":"B41","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00965.2024","article-title":"Revisiting hyper-resistance to muscle stretch in cerebral palsy: muscle hypo-extensibility is more of an issue than hyperreflexia","author":"Valad\u00e3o","year":"1985","journal-title":"J Appl Physiol"}],"container-title":["Frontiers in Pediatrics"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fped.2026.1832116\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T06:19:17Z","timestamp":1779949157000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fped.2026.1832116\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,28]]},"references-count":41,"alternative-id":["10.3389\/fped.2026.1832116"],"URL":"https:\/\/doi.org\/10.3389\/fped.2026.1832116","relation":{},"ISSN":["2296-2360"],"issn-type":[{"value":"2296-2360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,28]]},"article-number":"1832116"}}