{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T09:26:42Z","timestamp":1791451602764,"version":"4.3.3"},"reference-count":65,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2023,5,15]],"date-time":"2023-05-15T00:00:00Z","timestamp":1684108800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Journal of Anatomy"],"published-print":{"date-parts":[[2023,9]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Tree sloths evolved below\u2010branch locomotion making them one of few mammalian taxa beyond primates for which suspension is nearly obligatory. Suspension requires strong limb flexor muscles that provide both propulsion and braking\/support, and available locomotor kinetics data indicate that these roles differ between fore\u2010 and hindlimb pairs. Muscle structure in the pelvic limb is hypothesized to be a key anatomical correlate of function in braking\/support during suspensory walking and propulsion and\/or support during vertical climbing. This expectation was tested by quantifying architecture properties in the hindlimb limb musculature of brown\u2010throated three\u2010toed sloths (<jats:italic>Bradypus variegatus<\/jats:italic>: <jats:italic>N\u2009=<\/jats:italic>\u20097) to distinguish the roles of the flexor\/extensor functional muscle groups at each joint. Measurements of muscle moment arm (<jats:italic>r<\/jats:italic><jats:sub>m<\/jats:sub>), mass, belly length, fascicle length, pennation angle, and physiological cross\u2010sectional area (PCSA) were taken from <jats:italic>n\u2009=<\/jats:italic>\u200945 muscles. Overall, most muscles studied show properties for contractile excursion and fast joint rotational velocity. However, the flexor musculature is more massive (<jats:italic>p<\/jats:italic>\u2009=\u20090.048) and has larger PCSA (<jats:italic>p<\/jats:italic>\u2009=\u20090.003) than the extensors, especially at the knee joint and digits where well\u2010developed and strong flexors are capable of applying large joint torque. Moreover, selected hip flexors\/extensors and knee flexors have modified long <jats:italic>r<\/jats:italic><jats:sub>m<\/jats:sub> that can amplify applied joint torque in muscles with otherwise long, parallel fascicles, and one muscle (m. iliopsoas) was capable of moderately high power in <jats:italic>B. variegatus<\/jats:italic>. The architectural properties observed in the hip flexors and extensors match well with roles in suspensory braking and vertical propulsion, respectively, whereas strong knee flexors and digital flexors appear to be the main muscles providing suspensory support in the pelvic limb. With aid in support by the forelimbs and the use of adaptive slow locomotion and slow muscle fiber recruitment patterns, structure\u2013function in the tensile limb systems of sloths appears to collectively represent an additional mechanism for energy conservation.<\/jats:p>","DOI":"10.1111\/joa.13884","type":"journal-article","created":{"date-parts":[[2023,5,16]],"date-time":"2023-05-16T05:19:20Z","timestamp":1684214360000},"page":"448-466","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Muscle architectural properties indicate a primary role in support for the pelvic limb of three\u2010toed sloths (<i>Bradypus\u00a0variegatus<\/i>)"],"prefix":"10.1111","volume":"243","author":[{"given":"D. M.","family":"Morgan","sequence":"first","affiliation":[{"name":"Department of Chemical and Biological Sciences Youngstown State University  Ohio Youngstown USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K. B.","family":"Spainhower","sequence":"additional","affiliation":[{"name":"Department of Chemical and Biological Sciences Youngstown State University  Ohio Youngstown USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8841-9687","authenticated-orcid":false,"given":"A. M.","family":"Mossor","sequence":"additional","affiliation":[{"name":"Department of Anatomy and Neurobiology Northeast Ohio Medical University  Rootstown Ohio USA"},{"name":"School of Biomedical Sciences Kent State University  Kent Ohio USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. 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