Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions.

Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions. Research Abstract Details 

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Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions. Abstract Text:

F G Shellock,T Fukunaga,J H Mink,V R Edgerton,

Eccentric (lengthening) muscle actions involve the forced lengthening of active muscles. Compared with concentric (shortening) muscle actions subjected to the same relative work load, eccentric actions have lower oxygen consumption requirements, fewer activated motor units, and less lactate production. This study was conducted to determine if T2-weighted MR could show any difference in muscles performing these specific types of actions and, therefore, be useful for physiologic investigations of eccentric and concentric actions. Five subjects performed exhaustive exercise by doing isolated concentric actions (raising a dumbbell, flexing at the elbow) and eccentric muscle actions (lowering a dumbbell, extending the contralateral arm). T2-weighted MR images of the arms were obtained immediately before and after exercise. Muscles that performed concentric actions had increases in signal intensity, whereas muscles that performed eccentric actions showed little or no change. T2 relaxation times increased significantly (p less than .01) in all volunteers, but T2 relaxation times for the muscles that performed concentric actions were significantly higher than those for muscles that performed eccentric actions (p less than .01). Therefore, T2 times increased with both concentric and eccentric actions, but the images failed to show the changes in the muscles that performed the eccentric actions. These data demonstrate that assessment of T2 values can be used to distinguish between muscles that perform concentric actions and those that perform eccentric actions, and this phenomenon may be useful for further physiologic investigations of these specific types of muscle actions.

Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions. Publishing Authors By Initials

FG Shellock,T Fukunaga,JH Mink,VR Edgerton,

For similar musculoskeletal system: muscles research abstracts see: musculoskeletal system: muscles research

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Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions. Journal Published:

PUBLICATION TYPE: Journal Article

Journal: AJR. American journal of roentgenology

VOLUME: 156

Page Numbers: 765-8

Journal Abbreviation:

ISSN: 0361-803X

DAY: 15

MONTH: Apr

YEAR: 1991

Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions. Information

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LANGUAGE: eng

NlmUniqueID: 7708173

Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions. Keywords Mesh Terms:

KEYWORDS: Muscles

MESH TERMS: physiology

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Grant and Affiliation Information for Acute effects of exercise on MR imaging of skeletal muscle: concentric vs eccentric actions.

AFFILIATION: Tower Musculoskeletal Imaging Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048.

Country: UNITED STATES

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MEDLINETA: AJR Am J Roentgenol

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