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Changes in human skeletal muscle ultrastructure and force production after acute resistance exercise.

Authors
Gibala MJ; MacDougall JD; Tarnopolsky MA; Stauber WT; Elorriaga A
Source
J Appl Physiol 1995 Feb; 78(2):702-708
NIOSHTIC No.
20029389
Abstract
Muscle ultrastructure and contractile properties were examined before and after a single bout of resistance exercise (8 sets of 8 repetitions at 80% of 1 repetition maximum). Eight untrained males performed the concentric (Con) phase of arm-curl exercise with one arm and the eccentric (Ecc) phase with the other arm. Needle biopsies were obtained from biceps brachii before exercise (Base), immediately postexercise from each arm (post-Con and post-Ecc), and 48 h postexercise from each arm (48 h-Con and 48 h-Ecc). Electron microscopy was used to quantify the presence of disrupted fibers in each sample. Analysis of variance revealed a greater (P < or = 0.05) proportion of disrupted fibers in post-Con, post-Ecc, 48 h-Con, and 48 h-Ecc samples compared with Base. Significantly more fibers were disrupted in post-Ecc (82%) and 48 h-Ecc (80%) samples compared with post-Con (33%) and 48 h-Con (37%), respectively. Voluntary and evoked strength measurements recovered to Base values within 24 h in the Con arm but remained depressed (P < or = 0.05) for 72-96 h in the Ecc arm. These data indicate that both the raising and lowering phases of weightlifting produced myofibrillar disruption, with the greatest disruption occurring during the lowering phase.
Keywords
Skeletal system disorders; Musculoskeletal system disorders; Muscles; Microscopy; Sampling; Sampling methods; Muscle physiology; Skeletal system
Contact
William T. Stauber, Ph. D., Department of Physiology, West Virginia University, P.O. Box 9229, Morgantown, WV 26507-9229
CODEN
JAPHEV
Publication Date
19950201
Document Type
Journal Article
Funding Amount
141085
Funding Type
Grant
Fiscal Year
1995
Identifying No.
Grant-Number-R01-OH-002918
Issue of Publication
2
ISSN
8750-7587
Source Name
Journal of Applied Physiology
State
WV
Performing Organization
West Virginia University, Morgantown, West Virginia
Page last reviewed: April 9, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division