TY - JOUR
T1 - Inferring muscle functional roles of the ostrich pelvic limb during walking and running using computer optimization
AU - Rankin, Jeffery W.
AU - Rubenson, Jonas
AU - Hutchinson, John R.
N1 - Funding Information:
This project was partially supported by BBSRC and NERC grants (grant no. BB/I02204X/1 and NE/K004751/1 to J.R.H.) and fellowships from the NSF (to J.R.H.) and the Vice Principal of Research at the Royal Veterinary College (to J.W.R.).
Publisher Copyright:
© 2016 The Authors.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - Owing to their cursorial background, ostriches (Struthio camelus) walk and run with high metabolic economy, can reach very fast running speeds and quickly execute cutting manoeuvres. These capabilities are believed to be a result of their ability to coordinate muscles to take advantage of specialized passive limb structures. This study aimed to infer the functional roles of ostrich pelvic limb muscles during gait. Existing gait data were combined with a newly developed musculoskeletal model to generate simulations of ostrich walking and running that predict muscle excitations, force and mechanical work. Consistent with previous avian electromyography studies, predicted excitation patterns showed that individual muscles tended to be excited primarily during only stance or swing. Work and force estimates show that ostrich gaits are partially hip-driven with the bi-articular hip-knee muscles driving stance mechanics. Conversely, the knee extensors acted as brakes, absorbing energy. The digital extensors generated large amounts of both negative and positive mechanical work, with increased magnitudes during running, providing further evidence that ostriches make extensive use of tendinous elastic energy storage to improve economy. The simulations also highlight the need to carefully consider non-muscular soft tissues that may play a role in ostrich gait.
AB - Owing to their cursorial background, ostriches (Struthio camelus) walk and run with high metabolic economy, can reach very fast running speeds and quickly execute cutting manoeuvres. These capabilities are believed to be a result of their ability to coordinate muscles to take advantage of specialized passive limb structures. This study aimed to infer the functional roles of ostrich pelvic limb muscles during gait. Existing gait data were combined with a newly developed musculoskeletal model to generate simulations of ostrich walking and running that predict muscle excitations, force and mechanical work. Consistent with previous avian electromyography studies, predicted excitation patterns showed that individual muscles tended to be excited primarily during only stance or swing. Work and force estimates show that ostrich gaits are partially hip-driven with the bi-articular hip-knee muscles driving stance mechanics. Conversely, the knee extensors acted as brakes, absorbing energy. The digital extensors generated large amounts of both negative and positive mechanical work, with increased magnitudes during running, providing further evidence that ostriches make extensive use of tendinous elastic energy storage to improve economy. The simulations also highlight the need to carefully consider non-muscular soft tissues that may play a role in ostrich gait.
UR - http://www.scopus.com/inward/record.url?scp=84973299921&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84973299921&partnerID=8YFLogxK
U2 - 10.1098/rsif.2016.0035
DO - 10.1098/rsif.2016.0035
M3 - Article
C2 - 27146688
AN - SCOPUS:84973299921
SN - 1742-5689
VL - 13
JO - Journal of the Royal Society Interface
JF - Journal of the Royal Society Interface
IS - 118
M1 - 20160035
ER -