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Analysis of Skeletal Muscle Metrics as Predictors of Functional Task Performance (EORS_FOI)
Principal Investigator
Research Area:
Behavior and performance
Muscle physiology
Species Studied
Scientific Name: Homo sapiens Species: Human

Space flight induces a host of physiological changes that have harmful effects on human function in normal gravity. Upon entry into a gravitational environment, astronauts must cope with impairments in strength, balance, and the ability to ambulate. Although scientific investigations have begun to explain the underlying physiological mechanisms of these changes; the corresponding impairments in functional performance have yet to be quantified. Therefore, an interdisciplinary team was formed to systematically evaluate the impact of space flight induced physiological changes on the performance of functional tasks (e.g. ladder climbing, hatch opening). This collective effort is referred to as the Functional Task Test (FTT) project. The Exercise Physiology and Countermeasures Project has been instrumental in supporting the development of the functional tasks as well as developing the battery of skeletal muscle performance tests for the FTT project.

During space flight, astronauts experience alterations in muscle performance that may cause significant impairments in the performance of operational tasks immediately following landing on a planetary surface. The effects of reduced strength to body weight ratio on the performance of functional tests that are representative of critical mission tasks for lunar and Mars operations were examined. The investigators tested human subjects on an integrated suite of functional tests while wearing a special suit that allows external loads to be applied in order to manipulate subjects’ strength to body weight ratio. Ths study assisted investigators in 1) documenting the degree to which a reduction in strength to body weight ratio affects functional task performance, and 2) identifying critical strength to body weight thresholds that need to be protected in order to maintain task performance capability.

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Ryder JW, Buxton RE, Goetchius E, Scott-Pandorf M, Hackney KJ, Fiedler J, Ploutz-Snyder RJ, Bloomberg JJ, and Ploutz-Snyder LL. Influence of muscle strength to weight ratio on functional task performance. European Journal of Applied Physiology. 2012; Sep 26. []

Muscle strength
Body weight
Task performance and analysis

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Data Information
Data Availability
Archive is complete. Data sets are not publicly available but can be requested.
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Bench press MVC
Bench press fatigue index
Bench press maximal force, isokinetic
Bench press peak power
Bench press rate of force development, isokinetic
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
ECP 02/01/2005 12/31/2010 In Progress

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Jessica Keune
Institutional Support
National Aeronautics and Space Administration (NASA)