Microvibrations: an interrelation between heart beat, muscle tremor and resting muscle tone.

The phenomenon of microvibrations was described by Rohracher in Vienna in the 1950s. Microvibrations consist of oscillationns in the frequency range of 7 to 13 Hz which can be observed on the surface of the body during a complete muscle relaxation. We had the opportunity to study the changes of microvibrations and physiological tremor under the condition of weightlessness in the Russian Space Station MIR during the so called "Austromir" project and the following Russian long term flights including the record flight of cosmonaut Polyakow.