|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online October 21, 2004
Journal of Experimental Biology 207, 4165-4174 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01253
Adjusting muscle function to demand: joint work during acceleration in wild turkeys
Oregon State University, Department of Zoology, 3029 Cordley Hall, Corvallis, OR 97331-2914, USA
* Author for correspondence at present address: Brown University, Ecology and Evolutionary Biology Department, Box G-B205, Providence, RI 02912, USA (e-mail: thomas_roberts{at}brown.edu)
Accepted 17 August 2004
We measured the net work performed at hind limb joints in running turkeys to determine the source of mechanical power for acceleration. We tested the hypothesis that net mechanical work per step increases in proportion to acceleration at all four major hind limb joints (hip, knee, ankle and tarsometatarsal–phalangeal joint). This hypothesis was based on the idea that all hind limb muscles should contribute mechanical work to maximize performance during accelerations, and a previous study that indicated the mechanical power output of the entire turkey hind limb musculature was remarkably high. We used high-speed video and force-plate measurements to measure joint moment, velocity and power output during single foot-contacts of running accelerations. By measuring steps in which the animals were relatively more or less motivated to accelerate, we obtained data for a range of accelerations, all at approximately the same running speed. Net joint work per step increased at the hip and ankle as a function of acceleration. Hip net work per unit body mass was 0.12±0.09 J kg-1 averaged over the five lowest accelerations (–0.22±0.08 m s-2), and 0.87±0.20 J kg-1 for the five highest accelerations (4.86±0.27 m s-2). Ankle work was –0.21±0.11 J kg-1 for the lowest accelerations and 0.71±0.28 J kg-1 for the highest. The high work output at the ankle is consistent with the idea that elastic mechanisms function to increase muscle work during acceleration. The work performed at the knee and tarsometatarsal–phalangeal joint was independent of acceleration in a step. These results support the idea that hip and ankle extensors contribute significantly to the work necessary to accelerate the body.
We also measured the change in joint moment and angular excursion with acceleration to determine whether the mechanism for increasing work output at a joint involved an increase in muscle force or muscle shortening. The increase in joint work at the hip and ankle resulted almost entirely from an increase in joint angular excursion during stance. Hip extension increased by more than threefold from the lowest to the highest accelerations, and the angular excursion of the ankle increased from –24.8±4.7° (net flexion) at the lowest accelerations to 33.0±12.8° (net extension) at the highest accelerations. Mean stance joint moment was unchanged with acceleration at the ankle and increased by approximately 35% at the hip across the range of accelerations. These patterns of joint moment and excursion indicate that turkeys increase mechanical work for acceleration primarily by increasing muscle shortening, rather than muscle force.
Key words: locomotion, muscle work, muscle power, avian, running
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
Related articles in JEB:
This article has been cited by other articles:
|
|
 |
|
  R. M. Walter and D. R. Carrier Rapid acceleration in dogs: ground forces and body posture dynamics J. Exp. Biol., June 15, 2009; 212(12): 1930 - 1939. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Daley, A. Voloshina, and A. A. Biewener The role of intrinsic muscle mechanics in the neuromuscular control of stable running in the guinea fowl J. Physiol., June 1, 2009; 587(11): 2693 - 2707. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Schilling, T. Fischbein, E. P. Yang, and D. R. Carrier Function of the extrinsic hindlimb muscles in trotting dogs J. Exp. Biol., April 1, 2009; 212(7): 1036 - 1052. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. B. Williams, J. R. Usherwood, K. Jespers, A. J. Channon, and A. M. Wilson Exploring the mechanical basis for acceleration: pelvic limb locomotor function during accelerations in racing greyhounds (Canis familiaris) J. Exp. Biol., February 15, 2009; 212(4): 550 - 565. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. Richards The kinematic determinants of anuran swimming performance: an inverse and forward dynamics approach J. Exp. Biol., October 1, 2008; 211(19): 3181 - 3194. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Nakai, T. Azuma, M. Sudo, S.-i. Urayama, O. Takizawa, and S. Tsutsumi MRI analysis of structural changes in skeletal muscles and surrounding tissues following long-term walking exercise with training equipment J Appl Physiol, September 1, 2008; 105(3): 958 - 963. [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]
|
|
|
|
|
|
J. Rubenson, D. G. Lloyd, T. F. Besier, D. B. Heliams, and P. A. Fournier Running in ostriches (Struthio camelus): three-dimensional joint axes alignment and joint kinematics J. Exp. Biol., July 15, 2007; 210(14): 2548 - 2562. [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]
|
|
|
|
|
|
G. A. Lichtwark and A. M. Wilson Interactions between the human gastrocnemius muscle and the Achilles tendon during incline, level and decline locomotion J. Exp. Biol., November 1, 2006; 209(21): 4379 - 4388. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Dutto, D. F. Hoyt, H. M. Clayton, E. A. Cogger, and S. J. Wickler Joint work and power for both the forelimb and hindlimb during trotting in the horse J. Exp. Biol., October 15, 2006; 209(20): 3990 - 3999. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. E. Vereecke, K. D'Aout, and P. Aerts The dynamics of hylobatid bipedalism: evidence for an energy-saving mechanism? J. Exp. Biol., August 1, 2006; 209(15): 2829 - 2838. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. A. Lichtwark and A. M. Wilson Effects of series elasticity and activation conditions on muscle power output and efficiency J. Exp. Biol., August 1, 2005; 208(15): 2845 - 2853. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. P. McGowan, R. V. Baudinette, J. R. Usherwood, and A. A. Biewener The mechanics of jumping versus steady hopping in yellow-footed rock wallabies J. Exp. Biol., July 15, 2005; 208(14): 2741 - 2751. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. Roberts and R. A. Belliveau Sources of mechanical power for uphill running in humans J. Exp. Biol., May 15, 2005; 208(10): 1963 - 1970. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. P. McGowan, R. V. Baudinette, and A. A. Biewener Joint work and power associated with acceleration and deceleration in tammar wallabies (Macropus eugenii) J. Exp. Biol., January 1, 2005; 208(1): 41 - 53. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Phillips TURKEYS PUT THEIR HIPS AND ANKLES INTO IT J. Exp. Biol., November 1, 2004; 207(23): i - i. [Full Text] [PDF]
|
|
