Man in space

Sarkolab Experiment


Study of a relationship between the musculotendinous and neuromuscular changes defining or limiting the human contractile functions in a long-term space flight.


  • Characterize the reflex excitability of muscles in pre-, flight and post-flight conditions using electrical stimulation of the motor nerve and by testing the following: H-, T-reflexes, the muscle stretching reflex.
  • Evaluate elastic and mechanical properties of muscles in pre-, flight and post-flight conditions in the active and passive state by changing the position of the ankle joint (the range of motion) and measuring lateral stiffness (LS) of muscles.
  • Characterize activation of muscles and muscular endurance strength in case of voluntary and involuntary contractions (electrically induced) with record of the surface electromyogram (EMG) during the maximum and submaximum isometric and isokinetic contractions at a constant speed of movement and with record of M-responses.
  • Evaluate the features of changes in the muscle architecture (length and the inclination angle of the muscle bundles) in pre-, flight and post-flight conditions in the active and passive states.
  • Characterize changes of mechanical properties of soleus muscle (SM) tendon (the muscle stiffness and stretching determined by ultrasound visualization during isometric contractions with increasing force) before and after SF.
  • Assess the intrinsic properties of contractile and molecular pathways involved in the tissue adaptation before and after SF.
  • Asses the dynamic motor performance when carrying out a series of the motor tasks with external and without external loads.
  • Assess changes of functional properties of neuromuscular activity (NMA) before and after SF.
  • Evaluate changes of the accurate parameters of human voluntary movements before and after SF.
  • Analyze relative importance of the central and peripheral factors determining functional properties of human NMA and change of their specific contribution to the result of a long-term space flight.
  • Assess the degree of change of the following ratio: the joint angle the muscle fibre pennation angle in the active state under the effect of microgravity factors.
  • Assess the degree of change of the time and amplitude characteristics of lateral stiffness of human skeletal muscles after a long-term SF.

Used science hardware:

When conducting this experiment the following ESA and NASA science hardware is used:

  • MARES hardware is intended for fixation of a subject and record of the muscular and reflex contractions;
  • T61P EPM laptop with such an external disk as MARES-EPM Hard Disk provides control of product operation and conduct of examinations.
  • electrostimulator PEMS-2 (Percutaneous Electrical Muscle Stimulator) is intended for electrical stimulation of motor nerves innervating human skeletal muscles;
  • ultrasound system (NASA HRF Ultrasound device) is designed for ultrasound investigations of changes of human muscle architecture;
  • electromyograph (ESA EMG device) is intended for recording bioelectrical activity of muscles;
  • kit, namely MARES Consumables kit contains consumables to conduct examinations of one cosmonaut in compliance with the SE program;
  • kit such as MARE Ultrasound kit contains consumables for making ultrasound investigations in the scope of the experiment.

Expected Results:

A comprehensive study of the muscle changes is necessary to organize long-term space Expeditions.

Experiment Results:

The results of the experiment are information recorded using the MARES hardware, electrostimulator, electromyograph and ultrasound system, as well as the accompanying photos and video.

ISS Crew

Hoshide  AkihikoHoshide

leg Novitskiy Novitskiy

Petr Dubrov Dubrov

Mark Vande Hei Vande Hei

Robert Shane

Megan McArthur McArthur