QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online February 4, 2005
Journal of Experimental Biology 208, 771-786 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01432

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Soman, A. Articles by Biewener, A. A. Search for Related Content PubMed PubMed Citation Articles by Soman, A. Articles by Biewener, A. A. Social Bookmarking                         What's this?

Regional patterns of pectoralis fascicle strain in the pigeon Columba livia during level flight

Arya Soman, Tyson L. Hedrick and Andrew A. Biewener^*

Concord Field Station, Department of Organismic and Evolutionary Biology, Harvard University, Old Causeway Road, Bedford, MA 01730, USA

^* Author for correspondence (e-mail: biewener{at}fas.harvard.edu)

Accepted 6 December 2004

Regional fascicle strains were recorded in vivo from the pectoralis of carneau pigeons using sonomicrometry during level slow flight, together with regional electromyography (EMG) and deltopectoral crest (DPC) strain measurements of whole muscle force. Fascicle strain measurements were obtained at four sites within the pectoralis: the anterior (Ant), middle (Mid) and posterior (Post) sternobrachium (SB), and the smaller thoracobrachium (TB). Strains were also recorded along the intramuscular aponeurosis of the pectoralis to assess its `in-series' compliance with respect to strains of Post SB and TB fascicles. In-series segment strains were also obtained along Ant SB and Mid SB fascicles, which insert directly on the DPC without attaching to the intramuscular aponeurosis.

In-series segment strains differed from 2% to 17.2%, averaging differences of 6.1% at the Ant SB site and 1.4% at the Mid SB site. Temporal patterns of in-series fascicle segment strain were similar at both sites. Regional fascicle strains also exhibited similar temporal patterns of lengthening and shortening and were most uniform in magnitude at the Ant SB, Mid SB and TB sites (total strain: 33.7%, 35.9% and 33.2% respectively), but were smaller at the Post SB site (24.4%). Strains measured along the aponeurosis tracked the patterns of contractile fascicle strain but were significantly lower in magnitude (19.1%). Fascicle lengthening strains (+25.4%) greatly exceeded net shortening strains (-6.5%) at all sites.

Much of the variation in regional fascicle strain patterns resulted from variation of in vivo recording sites among individual animals, despite attempts to define consistent regions for obtaining in vivo recordings. No significant variation in EMG activation onset was found, but deactivation of the Ant SB occurred before the other muscle sites. Even so, the range of variation was small, with all muscle regions being activated midway through lengthening (upstroke) and turned off midway through shortening (downstroke). While subtle differences in the timing and rate of fascicle strain may relate to differing functional roles of the pectoralis, regional patterns of fascicle strain and activation suggest a generally uniform role for the muscle as a whole throughout the wingbeat cycle. Shorter fascicles located in more posterior regions of the muscle underwent generally similar strains as longer fascicles located in more anterior SB regions. The resulting differences in fiber length were accommodated by strain in the intramuscular aponeurosis and rotation of the pectoralis insertion with respect to the origin. As a result, longer Ant and Mid SB fascicles were estimated to contribute substantially more work per unit mass than shorter Post SB and TB fascicles. When the mass fractions of these regions are accounted for, our regional fascicle strain measurements show that the anterior regions of the pectoralis likely contribute 76%, and the posterior regions 24%, of the muscle's total work output. When adjusted for mass fraction and regional fascicle strain, pectoralis work averaged 24.7±5.1 J kg^-1 (206.6±43.5 W kg^-1) during level slow (4-5 m s^-1) flight.

Key words: muscle, pectoralis, strain, work, flight, bird, sonomicrometry

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				J. T. Thompson, K. R. Taylor, and C. Gentile Gradients of strain and strain rate in the hollow muscular organs of soft-bodied animals Biol Lett, January 27, 2010; (2010): rsbl.2009.0978v1 - rsbl20090978. [Abstract] [Full Text] [PDF]

				N. J. Cronin, M. Ishikawa, M. J. Grey, R. af Klint, P. V. Komi, J. Avela, T. Sinkjaer, and M. Voigt Mechanical and neural stretch responses of the human soleus muscle at different walking speeds J. Physiol., July 1, 2009; 587(13): 3375 - 3382. [Abstract] [Full Text] [PDF]

				T. E Higham and A. A Biewener Fatigue alters in vivo function within and between limb muscles during locomotion Proc R Soc B, March 22, 2009; 276(1659): 1193 - 1197. [Abstract] [Full Text] [PDF]

				J. M Wakeling The recruitment of different compartments within a muscle depends on the mechanics of the movement Biol Lett, February 23, 2009; 5(1): 30 - 34. [Abstract] [Full Text] [PDF]

				T. E. Higham and A. A. Biewener Integration within and between muscles during terrestrial locomotion: effects of incline and speed J. Exp. Biol., July 15, 2008; 211(14): 2303 - 2316. [Abstract] [Full Text] [PDF]

				N. J. Cronin, J. Peltonen, M. Ishikawa, P. V. Komi, J. Avela, T. Sinkjaer, and M. Voigt Effects of contraction intensity on muscle fascicle and stretch reflex behavior in the human triceps surae J Appl Physiol, July 1, 2008; 105(1): 226 - 232. [Abstract] [Full Text] [PDF]

				A. M. Berg and A. A. Biewener Kinematics and power requirements of ascending and descending flight in the pigeon (Columba livia) J. Exp. Biol., April 1, 2008; 211(7): 1120 - 1130. [Abstract] [Full Text] [PDF]

				T. E Higham, A. A Biewener, and J. M Wakeling Functional diversification within and between muscle synergists during locomotion Biol Lett, February 23, 2008; 4(1): 41 - 44. [Abstract] [Full Text] [PDF]

				B. W. Tobalske and A. A. Biewener Contractile properties of the pigeon supracoracoideus during different modes of flight J. Exp. Biol., January 15, 2008; 211(2): 170 - 179. [Abstract] [Full Text] [PDF]

				D. J. Ellerby and G. N. Askew Modulation of flight muscle power output in budgerigars Melopsittacus undulatus and zebra finches Taeniopygia guttata: in vitro muscle performance J. Exp. Biol., November 1, 2007; 210(21): 3780 - 3788. [Abstract] [Full Text] [PDF]

				B. W. Tobalske Biomechanics of bird flight J. Exp. Biol., September 15, 2007; 210(18): 3135 - 3146. [Abstract] [Full Text] [PDF]

				C. P. McGowan, R. V. Baudinette, and A. A. Biewener Modulation of proximal muscle function during level versus incline hopping in tammar wallabies (Macropus eugenii) J. Exp. Biol., April 1, 2007; 210(7): 1255 - 1265. [Abstract] [Full Text] [PDF]

				G. B. Gillis, J. P. Flynn, P. McGuigan, and A. A. Biewener Patterns of strain and activation in the thigh muscles of goats across gaits during level locomotion J. Exp. Biol., December 15, 2005; 208(24): 4599 - 4611. [Abstract] [Full Text] [PDF]