Myotonometric Measurements of Muscle Health During Prolonged Human Exposure to Microgravity Environments

Lead Investigator: Charles T. Leonard, University of Montana

The loss of human muscle mass, strength, endurance and tone associated with prolonged exposure to microgravity in space are limiting factors for future manned space missions.  Physiological monitoring of muscle health during ground-based microgravity simulation experiments have included isokinetic strength testing (current gold-standard), magnetic resonance imaging (MRI) of muscle mass and near-infrared spectroscopy measurements of muscle oxygenation levels.  These approaches, however, have many disadvantages and are unlikely to transition to space.  New muscle health monitoring techniques that are portable, accurate, muscle specific, and reliable without being time or energy consuming are being sought by NASA. 

Proposed is a project to evaluate the Myotonometer, a portable electronic device that quantifies muscle tone, stiffness and strength, as an alternative tool to monitor muscle health during ground-based and spaceflight experiments.  The project goals are:  1) to determine the statistical relationships between Myotonomer data with NASA�s currently used ground-based muscle health assessment methods and 2) to involve undergraduate and graduate students in NASA-related muscle physiology research. 

Two sets of experiments are planned.  The first will obtain myotonometric measurements of muscle stiffness and strength of twin pairs during bedrest studies (NASA�s ground-based microgravity simulation).  Myotonometric measurements will be compared and correlated to results obtained with isokinetic and MRI testing.  The second set of experiments will obtain normative myotonometric and near-infrared spectroscopy data of human subjects.  These data will be used to examine the statistical relationships among myotonometric measurements of muscle stiffness and muscle oxygenation levels measured by near-infrared spectroscopy.