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Updated: Aug 15, 2026

Force and Position Control in Humans - The Role of Augmented Feedback
Published on: June 19, 2016
Afferent and peripheral control of muscle fiber properties during gravitational unloading
B S Shenkman1, K S Litvinova, T L Nemirovskaya
1SRC Institute for Biomedical Problems, RAS, Moscow, Russia. shenkman@imbp.ru
Abstract:
The present paper covers two series of the experiment studies performed in attempt to analyze the support-triggered cellular mechanisms, controlling the maintenance of tonic muscle fiber characteristics. Exposure to 7 day dry immersion induced significant decline of the human soleus single fiber peak isometric tension and the Ca(2+)-sensitivity of myofibrils. 30-40% losses of the relative content of titin and nebulin were found after immersion. The application of the plantar support stimulation device prevented all these alterations. In the second experimental series the treatment of hindlimb suspended rats with the Ca(2+)-binding agent (EGTA) allowed to prevent or attenuate all the above mentioned unloading-induced soleus fiber alterations. Thus it is concluded that resting Ca2+ accumulation in the unloaded fibers may be among the mechanisms involved in the changes of fiber properties during unloading.
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