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Muscular Deconditioning and its Prevention in Space Flight (SkyMusc)
Research Area:
Muscle physiology
Species Studied
Scientific Name: Homo sapiens Species: Human


The objective of this study was to quantify muscle strength losses in the arms and legs of all Skylab program crewmen by comparing preflight and postflight force and work measurements taken on an isokinetic dynamometer. The experiment instituted an initial minimum impact muscle function test, and as the missions demanded, added exercises and exercise devices and expanded the testing. This resulted in different exercise environments on each flight, such that there were actually three experiments, with the results of each flight affecting the next. The flights and countermeasures used inflight are described chronologically. Only aspects of skeletal muscle condition are addressed by this study, as cardiovascular aspects of conditioning and use of the bicycle ergometer are addressed in another Skylab experiment.

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LaFevers EV, Nicogossian AE, Hoffler GW, Hursta WN, and Baker J. SPECTRAL ANALYSIS OF SKELETAL MUSCLE CHANGES RESULTING FROM 59 DAYS OF WEIGHTLESSNESS IN SKYLAB. National Aeronautics and Space Administration TM X-58171, 1975.

LaFevers EV. Power spectral density analysis of the electromyogram from a work task performed in a full pressure suit [dissertation]. Houston, Texas: University of Houston; 1974.

LaFevers EV. Evaluation of localized muscle fatigue using power spectral density analysis of the electromyogram. In: Human Factors Society, Annual Meeting, 18th, Huntsville, Ala., October 15-17, 1974. (A75-19676 07-54) Santa Monica, Calif., Human Factors Society, 1974, p. 278-283.

Thornton WE. Muscular Deconditioning and its Prevention in Space Flight: The Proceedings of the Skylab Life Sciences Symposium, Lyndon B. Johnson Space Center, 27-29 August 1974. Houston, Texas: National Aeronautics and Space Administration; 1974.

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Body mass
Body weight
Leg volume
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Skylab 2 05/25/1973 06/22/1973 28 days
Skylab 3 07/28/1973 09/25/1973 59.5 days
Skylab 4 11/16/1973 02/08/1974 84 days

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
National Aeronautics and Space Administration (NASA)