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

Characterization of isometric contractions of rat skeletal muscle in vivo: duty cycle effects.

Authors
Geronilla-K; Wu-JZ; Baker-BA; Cutlip-RG
Source
Bio-Med Mater Eng 2006 Dec; 16(6):369-380
NIOSHTIC No.
20031462
Abstract
Many work related injuries stem from the exertion of skeletal muscle forces over an extended period of time. Musculoskeletal injury can be caused by muscle's inability to maintain force during occupational exposure. The goal of the present study is to test how various rest times (duty cycles) between long isometric contractions will affect decrements in force, and develop a model that characterizes force decrements due to skeletal muscle fatigue. All tests were performed in vivo on the tibialis anterior muscle of anesthetized Sprague-Dawley rats. Animals were randomly assigned to either a 10 second (N=8), 1 minute (N=8), or 5 minute (N=8) duty cycle group. All animals were then subjected to 7 isometric contractions (duration of 2.8 seconds). A model was constructed to characterize forces changes over the duration of a contraction and over multiple contractions. The model consisted of a power law and an exponential component; these two components were combined by using an exponential weighting function. Overall, the combination of a power law and exponential model with a weighting function satisfactorily characterized the changes in isometric force for the 10 second duty cycle, but a simpler exponential model could be used where longer duty cycles are performed.
Keywords
Occupational-exposure; Risk-factors; Laboratory-animals; Animals; Animal-studies; Musculoskeletal-system; Injuries; Musculoskeletal-system-disorders; Cumulative-trauma; Cumulative-trauma-disorders
Contact
RG Cutlip, NIOSH, 1095 Willowdale Rd, Morgantown, WV 26505
CODEN
BMENEO
Publication Date
20061201
Document Type
Journal Article
Email Address
RGC8@cdc.gov
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
6
ISSN
0959-2989
NIOSH Division
HELD
Priority Area
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Source Name
Bio-Medical Materials and Engineering
State
WV
TOP