Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Force output during and following active stretches of rat plantar flexor muscles: effect of velocity of ankle rotation.

Authors
Willems-MET; Stauber-WT
Source
J Biomech 2000 Aug; 33(8):1035-1038
NIOSHTIC No.
20024463
Abstract
During the development of force deficits by repeated stretches, velocity-sensitive changes in the extra force produced during and after subsequent stretching has not been studied. In the present study, repeated dorsiflexion of the foot of rats with maximally contracting plantar flexor muscles was performed at two angular velocities [0.87 (slow muscle stretch) and 10.47rads(-1) (fast muscle stretch)] to examine the active force of the muscles during and following dorsiflexion. Dorsiflexion was performed 30 times with a rest period of 3min between the stretches to minimize muscle fatigue. The ability of rat plantar flexor muscles to produce additional force during the stretch was not velocity sensitive. In contrast, repeated dorsiflexion with fast muscle stretches, but not with slow muscle stretches, resulted in an increase in the force decay with time following the stretches (i.e. increased stress relaxation), as indicated by a change in the time constant of force decay during stress relaxation. Apparently, the stress-relaxation of rat plantar flexor muscles is sensitive to angular velocity of ankle movements; repeated fast, but not slow dorsiflexion, alters the stress relaxation process of active skeletal muscles exposed to stretches which create a force deficit. The change in time constant of force decay during stress relaxation in response to a series of repeated stretches might provide information on the sarcomere length distribution in skeletal muscles.
Keywords
Musculoskeletal-system-disorders; Stress; Laboratory-animals; Animals; Animal-studies; Fatigue; Muscle-stress; Muscle-tension; Skeletal-stress; Skeletal-system-disorders
Contact
Department of Physiology, West Virginia University, P.O. Box 9229, Morgantown, WV 26506, USA
CODEN
JBMCB5
Publication Date
20000801
Document Type
Journal Article
Email Address
mwillems@hsc.wvu.edu
Funding Amount
868663
Funding Type
Grant
Fiscal Year
2000
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-002918
Issue of Publication
8
ISSN
0021-9290
Priority Area
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Source Name
Journal of Biomechanics
State
WV
Performing Organization
West Virginia University, Morgantown, West Virginia
TOP