|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online December 2, 2005
Journal of Experimental Biology 208, 4599-4611 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01940
Patterns of strain and activation in the thigh muscles of goats across gaits during level locomotion
1 Department of Biological Sciences, Mount Holyoke College, South Hadley, MA
01075, USA
2 Concord Field Station, Harvard University, Old Causeway Road, Bedford, MA
01730, USA
* Author for correspondence (e-mail: ggillis{at}mtholyoke.edu)
Accepted 18 October 2005
Unlike homologous muscles in many vertebrates, which appear to function similarly during a particular mode of locomotion (e.g. red muscle in swimming fish, pectoralis muscle in flying birds, limb extensors in jumping and swimming frogs), a major knee extensor in mammalian quadrupeds, the vastus lateralis, appears to operate differently in different species studied to date. In rats, the vastus undergoes more stretching early in stance than shortening in later stance. In dogs, the reverse is true; more substantial shortening follows small amounts of initial stretching. And in horses, while the vastus strain trajectory is complex, it is characterized mainly by shortening during stance. In this study, we use sonomicrometry and electromyography to study the vastus lateralis and biceps femoris of goats, with three goals in mind: (1) to see how these muscles work in comparison to homologous muscles studied previously in other taxa; (2) to address how speed and gait impact muscle actions and (3) to test whether fascicles in different parts of the same muscle undergo similar length changes. Results indicate that the biceps femoris undergoes substantial shortening through much of stance, with higher strains in walking and trotting [32–33% resting length (L0)] than galloping (22% L0). These length changes occur with increasing biceps EMG intensities as animals increase speed from walking to galloping. The vastus undergoes a stretch–shorten cycle during stance. Stretching strains are higher during galloping (15% L0) than walking and trotting (9% L0). Shortening strains follow a reverse pattern and are greatest in walking (24% L0), intermediate in trotting (20% L0) and lowest during galloping (17% L0). As a result, the ratio of stretching to shortening increases from below 0.5 in walking and trotting to near 1.0 during galloping. This increasing ratio suggests that the vastus does relatively more positive work than energy absorption at the slower speeds compared with galloping, although an understanding of the timing and magnitude of force production is required to confirm this. Length-change regimes in proximal, middle and distal sites of the vastus are generally comparable, suggesting strain homogeneity through the muscle. When strain rates are compared across taxa, vastus shortening velocities exhibit the scaling pattern predicted by theoretical and empirical work: fascicles shorten relatively faster in smaller animals than larger animals (strain rates near 2 L s–1 have been reported for trotting dogs and were found here for goats, versus 0.6–0.8 L s–1 reported in horses). Interestingly, biceps shortening strain rates are very similar in both goats and rats during walking (1–1.5 L s–1) and trotting (1.5–2.5 L s–1, depending on speed of trot), suggesting that the ratio of in vivo shortening velocities (V) to maximum shortening velocities (Vmax) is smaller in small animals (because of their higher Vmax).
Key words: locomotion, gait, muscle, electromyography, sonomicrometry, goat, biceps femoris, vastus lateralis
This article has been cited by other articles:
|
|
 |
|
  A. M. Carroll, D. V. Lee, and A. A. Biewener Differential muscle function between muscle synergists: long and lateral heads of the triceps in jumping and landing goats (Capra hircus) J Appl Physiol, October 1, 2008; 105(4): 1262 - 1273. [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]
|
|
|
|
 |
|
 A. M. Gabaldon, F. E. Nelson, and T. J. Roberts Relative shortening velocity in locomotor muscles: turkey ankle extensors operate at low V/Vmax Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2008; 294(1): R200 - R210. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. N. Dean, E. Azizi, and A. P. Summers Uniform strain in broad muscles: active and passive effects of the twisted tendon of the spotted ratfish Hydrolagus colliei J. Exp. Biol., October 1, 2007; 210(19): 3395 - 3406. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. Roberts, B. K. Higginson, F. E. Nelson, and A. M. Gabaldon Muscle strain is modulated more with running slope than speed in wild turkey knee and hip extensors J. Exp. Biol., July 15, 2007; 210(14): 2510 - 2517. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Nishikawa, A. A. Biewener, P. Aerts, A. N. Ahn, H. J. Chiel, M. A. Daley, T. L. Daniel, R. J. Full, M. E. Hale, T. L. Hedrick, et al. Neuromechanics: an integrative approach for understanding motor control Integr. Comp. Biol., July 1, 2007; 47(1): 16 - 54. [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]
|
|
|
|
|
|
M. A. Daley, G. Felix, and A. A. Biewener Running stability is enhanced by a proximo-distal gradient in joint neuromechanical control J. Exp. Biol., February 1, 2007; 210(3): 383 - 394. [Abstract] [Full Text] [PDF]
|
|
