Computational modelling of muscle fibre operating ranges in the hindlimb of a small ground bird (Eudromia elegans), with implications for modelling locomotion in extinct species

• DOI: 10.1371/journal.pcbi.1008843
• Publication Date: 2021-04-01T17:55:51Z
• Authors: Peter J. Bishop; Krijn B. Michel; Antoine Falisse; Andrew R. Cuff; Vivian R. Allen; Friedl De Groote; John R. Hutchinson
• Keywords: Hindlimb; Muscle fibre

The arrangement and physiology of muscle fibres can strongly influence musculoskeletal function whole-organismal performance. However, experimental investigation during in vivo activity is typically limited to relatively few muscles a given system. Computational models simulations the system partly overcome these limitations, by exploring dynamics muscles, tendons other tissues robust quantitative fashion. Here, high-fidelity, 26-degree-of-freedom model was developed hindlimb small ground bird, elegant-crested tinamou ( Eudromia elegans , ~550 g), including all major limb (36 actuators per leg). integrated with biplanar fluoroscopy (XROMM) forceplate data for walking running, where dynamic optimization used estimate excitations fibre length changes throughout both gaits. Following this, series static over total range physiological postures were performed, circumscribe bounds possible variation length. During gait, lengths remained between 0.5 1.21 times optimal length, but operated mostly on ascending plateau active force-length curve, result that parallels previous findings birds, humans species. ranges varied considerably among individual especially when considered across joint excursion. Net change muscle–tendon units less than sometimes markedly so, suggesting approaches use extinct species are likely underestimating this important parameter many muscles. results study clarify broaden understanding extant animals, help refine