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Neuromuscular activation patterns during treadmill walking after space flightAstronauts adopt a variety of neuromuscular control strategies during space flight that are appropriate for locomoting in that unique environment, but are less than optimal upon return to Earth. We report here the first systematic investigation of potential adaptations in neuromuscular activity patterns associated with postflight locomotion. Astronaut-subjects were tasked with walking on a treadmill at 6.4 km/h while fixating a visual target 30 cm away from their eyes after space flights of 8-15 days. Surface electromyography was collected from selected lower limb muscles and normalized with regard to mean amplitude and temporal relation to heel strike. In general, high correlations (more than 0.80) were found between preflight and postflight activation waveforms for each muscle and each subject: however relative activation amplitude around heel strike and toe off was changed as a result of flight. The level of muscle cocontraction and activation variability, and the relationship between the phasic characteristics of the ankle musculature in preparation for toe off also were altered by space flight. Subjects also reported oscillopsia during treadmill walking after flight. These findings indicate that, after space flight, the sensory-motor system can generate neuromuscular-activation strategies that permit treadmill walking, but subtle changes in lower-limb neuromuscular activation are present that may contribute to increased lower limb kinematic variability and oscillopsia also present during postflight walking.
Document ID
20040173070
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Layne, C. S.
(KRUG Life Sciences Houston, TX 77058-2769, United States)
McDonald, P. V.
Bloomberg, J. J.
Date Acquired
August 22, 2013
Publication Date
January 1, 1997
Publication Information
Publication: Experimental brain research. Experimentelle Hirnforschung. Experimentation cerebrale
Volume: 113
Issue: 1
ISSN: 0014-4819
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Flight Experiment
short duration
NASA Discipline Neuroscience
Clinical Trial
NASA Center JSC
STS Shuttle Project
manned

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