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

Ankle position during isometric contractions alters stretch-induced force deficits of rat plantar flexor muscles.

Authors
Willems-ME; Stauber-WT
Source
Med Sci Sports Exerc 1999 May; 31(Suppl 5):S74
NIOSHTIC No.
20029518
Abstract
This study examined the effect of forceful isometric contractions at long and short muscle lengths on the force deficit induced by active stretches (15) of the plantar flexor muscles in intact rats. Ankle position of 0.70 rad and 2.09 rad was considered a long (ISO-LONG) and short muscle length (ISO-SHORT), respectively. Three isometric contractions of 1900 ms and 3 min rests were performed prior to the stretches. Rats without preceding isometric contractions (ISO-NO) served as controls. For all groups (n = 4 each), maximal isometric forces at 2.09 rad were similar (ISO-NO: 22.7 +/- 2.1 N; ISO-LONG: 23.3 +/- 1.0 N; ISO-SHORT: 22.2 +/- 1.7 N). Stretches (one every 3 min) were imposed on maximally active muscle by ankle rotation from 1.57 to 0.70 rad (velocity 0.87 rad s-1). Following ISO-NO and ISO-SHORT, similar force levels (at 1.57 rad) preceded the first ankle rotation. Force levels following ISO-LONG were 25% lower. In all groups, force decreased exponentially with half of the total force deficit within the first five strains. The force for ISO-LONG was decreased to 76.3 +/- 3.8% and significantly less than for ISO-NO and ISO-SHORT (to 60.7 +/- 3.1% and 58.3 +/- 4.1%, respectively). It is concluded that the reduction of force deficits by repeated strains following forceful isometric contractions is dependent on ankle position during the isometric contractions. Isometric conditioning appears to protect from muscle injury (i.e. force deficits) particularly when performed at long muscle lengths.
Keywords
Muscles; Laboratory-animals; Animals; Animal-studies; Fatigue; Skeletal-system; Musculoskeletal-system
Contact
Department of Biochemistry, P.O. Box 9142, West Virginia University Health Sciences Center, Morgantown, WV 26506-9142
CODEN
MSPEDA
Publication Date
19990501
Document Type
Abstract
Funding Amount
868663
Funding Type
Grant
Fiscal Year
1999
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-002918
ISSN
0195-9131
Priority Area
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Source Name
Medicine and Science in Sports and Exercise
State
WV
Performing Organization
West Virginia University, Morgantown, West Virginia
TOP