title: Contractile characteristics of the triceps surae muscle in healthy males during 120-days head-down tilt (HDT) and countermeasures.
abstract: To reveal mechanisms responsible for changes in muscle contractility during microgravity, it seems expedient to perform similar studies under microgravity or conditions simulating microgravity.  Among standard methods for simulating microgravity, hypokinesia modelling support unloading (or rather its redistribution), and hypodynamia are employed.  Absence of weight loading, decreased muscular effort characteristic of the Earth conditions due to counteracting gravity, results in a general muscle underloading and therefore in lowered activity of the proprioceptive input.  This may be one of the reasons not only for a resetting of motor coordination and control, but also for a gradual development of a persistent change in the motor control system.  The basis of countermeasures against negative consequences of microgravity (hypokinesia) is the correct choice of countermeasures.  In this connection of specific interest is a study of the magnitude of change in skeletal muscle contractility in humans after a variety of countermeasures when functional activity is lowered by a long-term 120-days HDT which is an adequate simulation of physiological microgravity-induced effects.
authors.affiliation: Institute of Biomedical Problems, Ministry of Public Health, Moscow, Russia.
authors.forename: Y A
authors.initials: YA
authors.lastname: Koryak
mesh_terms: D000328:Adult; D001510:Bed Rest; D001842:Bone and Bones / Q000502:physiology; D004358:Drug Therapy; D005081:Exercise Therapy; D018475:Head-Down Tilt; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation