{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,27]],"date-time":"2026-09-27T21:40:10Z","timestamp":1790545210573,"version":"4.1.0"},"reference-count":26,"publisher":"The Company of Biologists","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Summary<\/jats:title>\n               <jats:p>Often the human Achilles tendon (AT) has been considered to act as a single elastic structure in series with the muscles of the triceps-surae. As such it has been commonly modelled as a hookean spring of uniform stiffness. However, the free AT and the proximal AT have distinctly different structures which lend themselves to different elastic properties. This study aimed to use three-dimensional freehand ultrasound imaging to determine if the proximal AT and free AT exhibit different elastic behaviour during sub-maximal, fixed-end contractions of the triceps-surae. Six male and five female participants (mean \u00b1 sd age = 27 \u00b1 5 years) performed fixed position contractions of the plantar-flexors on an isokinetic dynamometer at 50% of their maximum voluntary contraction in this position. Freehand 3D ultrasound imaging was used to reconstruct the free-tendon and proximal AT at rest and during contraction. The free-tendon exhibited significantly (P = 0.03) greater longitudinal strain (5.2 \u00b1 1.7%) than the proximal AT (2.6 \u00b1 2.0%). The lesser longitudinal strain of the proximal AT was linked to the fact that it exhibited considerable transverse (orthogonal to the longitudinal direction) strains (5.0% \u00b1 4). The transverse strain of the proximal AT is likely due to the triceps-surae muscles bulging upon contraction and thus, the level of bulging may influence the elastic behaviour of the proximal AT. This might have implications for the understanding of triceps-surae muscle-tendon interaction during locomotion, tendon injury mechanics and previous measurements of AT elastic properties.<\/jats:p>","DOI":"10.1242\/jeb.077131","type":"journal-article","created":{"date-parts":[[2012,11,2]],"date-time":"2012-11-02T06:32:29Z","timestamp":1351837949000},"source":"Crossref","is-referenced-by-count":50,"title":["Differential strain patterns of the human Achilles tendon determined <i>in vivo<\/i> with freehand three-dimensional ultrasound imaging"],"prefix":"10.1242","author":[{"given":"Dominic J.","family":"Farris","sequence":"first","affiliation":[{"name":"University of North Carolina-Chapel Hill & North Carolina State University, USA;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Grant","family":"Trewartha","sequence":"additional","affiliation":[{"name":"University of Bath, UK;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. Polly","family":"McGuigan","sequence":"additional","affiliation":[{"name":"University of Bath, UK;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Glen A.","family":"Lichtwark","sequence":"additional","affiliation":[{"name":"University of Queensland, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"237","published-online":{"date-parts":[[2012,1,1]]},"reference":[{"key":"2021042507142580100_R1","doi-asserted-by":"crossref","first-page":"4309","DOI":"10.1113\/jphysiol.2009.173690","article-title":"Biaxial strain and variable stiffness in aponeuroses","volume":"587","author":"Azizi","year":"2009","journal-title":"J. Physiol."},{"key":"2021042507142580100_R2","doi-asserted-by":"crossref","first-page":"1313","DOI":"10.1016\/j.jbiomech.2009.03.005","article-title":"Validation of a freehand 3D ultrasound system for morphological measures of the medial gastrocnemius muscle","volume":"42","author":"Barber","year":"2009","journal-title":"J. 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Physiol."},{"key":"2021042507142580100_R6","doi-asserted-by":"crossref","first-page":"1430","DOI":"10.1152\/jappl.1996.81.3.1430","article-title":"Tendinous movement of a human muscle during voluntary contractions determined by real-time ultrasonography","volume":"81","author":"Fukunaga","year":"1996","journal-title":"J. Appl. Physiol."},{"issue":"Suppl. 2","key":"2021042507142580100_R7","doi-asserted-by":"crossref","first-page":"S186","DOI":"10.1259\/bjr\/80676194","article-title":"Processing and visualizing three-dimensional ultrasound data","volume":"77","author":"Gee","year":"2004","journal-title":"Br. J. Radiol."},{"key":"2021042507142580100_R8","doi-asserted-by":"crossref","first-page":"603","DOI":"10.1152\/japplphysiol.00189.2005","article-title":"Muscle-tendon interaction and elastic energy usage in human walking","volume":"99","author":"Ishikawa","year":"2005","journal-title":"J. Appl. Physiol."},{"key":"2021042507142580100_R9","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1016\/j.gaitpost.2006.05.002","article-title":"Medial gastrocnemius muscle behavior during human running and walking","volume":"25","author":"Ishikawa","year":"2007","journal-title":"Gait Posture"},{"key":"2021042507142580100_R10","volume-title":"Human Tendons: Anatomy, Physiology and Pathology","author":"J\u00f3zsa","year":"1997"},{"key":"2021042507142580100_R11","doi-asserted-by":"crossref","first-page":"597","DOI":"10.7600\/jspfsm1949.48.597","article-title":"Visco-elastic properties of tendon structures in human medial gastrocnemius muscle","volume":"48","author":"Kubo","year":"1999","journal-title":"Jpn. J. Phys. 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Biomech."},{"key":"2021042507142580100_R15","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.jbiomech.2004.03.024","article-title":"Validity of procedures involved in ultrasound-based measurement of human plantarflexor tendon elongation on contraction","volume":"38","author":"Maganaris","year":"2005","journal-title":"J. Biomech."},{"key":"2021042507142580100_R16","doi-asserted-by":"crossref","first-page":"1453","DOI":"10.1016\/S0021-9290(00)00099-3","article-title":"In-vivo human tendinous tissue stretch upon maximum muscle force generation","volume":"33","author":"Maganaris","year":"2000","journal-title":"J. Biomech."},{"key":"2021042507142580100_R17","doi-asserted-by":"crossref","first-page":"1639","DOI":"10.1016\/S0021-9290(02)00240-3","article-title":"Tensile properties of the in vivo human gastrocnemius tendon","volume":"35","author":"Maganaris","year":"2002","journal-title":"J. Biomech."},{"key":"2021042507142580100_R18","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1046\/j.1469-7580.2001.19940449.x","article-title":"Changes in aponeurotic dimensions upon muscle shortening: in vivo observations in man","volume":"199","author":"Maganaris","year":"2001","journal-title":"J. Anat."},{"key":"2021042507142580100_R19","doi-asserted-by":"crossref","first-page":"2089","DOI":"10.1152\/japplphysiol.00604.2002","article-title":"Repeated contractions alter the geometry of human skeletal muscle","volume":"93","author":"Maganaris","year":"2002","journal-title":"J. Appl. Physiol."},{"key":"2021042507142580100_R20","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1046\/j.1365-201X.2003.01048.x","article-title":"Differential strain patterns of the human gastrocnemius aponeurosis and free tendon, in vivo","volume":"177","author":"Magnusson","year":"2003","journal-title":"Acta Physiol. 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