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Evaluation of the MuscleLab Power Testing System using Bench Press and Leg Press Exercise (ROI_MusLab)
Principal Investigator
Research Area:
Exercise physiology
Muscle physiology
Technology development
Species Studied
Scientific Name: Homo sapiens Species: Human

The National Aeronautics and Space Administration (NASA), European Space Agency (ESA), and Russian Space Agency have initiated a project to identify a standard set of pre- and post flight tests to evaluate crew health and performance capabilities. The testing program is called the Clinical Status Evaluation (CSE) and will include measures of muscle strength and endurance.

Space Shuttle and International Space Station (ISS) crew members have experienced decreases in muscle strength and endurance as a result of space flight. Historically, NASA has used isokinetic strength testing of the lower extremity as its primary method of pre- and post flight muscle strength testing. Isokinetic strength testing uses a dynamometer to measure joint torque at selected angular velocities, and is safe for clinical research. However, functional tasks conducted in 1-G, such as walking and running, require muscle contraction at variable joint velocities, accelerations, and variable resulting forces. It has been suggested that free weight testing is a better testing mode for the evaluation of functional muscular strength. Additionally, it has been suggested that free weight testing is a valid and a safe mode of testing for various populations.

MuscleLab (Ergotest Technology, Langesund, Norway) is a commercial device that measures the lifting velocity and calculates the average power output of a barbell during free weight strength testing. The device consists of a linear encoder that can be attached to a bar or sliding rack to track displacement and velocity. A "user-friendly" software program uses the known mass of the bar and measured velocity to calculate average power. MuscleLab (ML) also uses power from sub-maximal lifts to estimate a one-repetition maximum lift (1-RM). ML is already used by ESA to test their astronauts for changes in power.

Investigators evaluated free weight muscle power testing with ML to determine it's usefulness for CSE testing. The objectives of the study were:

  1. to determine the reliability of 1-RM lifting with a Smith machine bench press (BP) and Cybex leg press (LP)
  2. to determine the load at which the greatest average power occurs for the BP and LP
  3. to determine the reliability of power measures from different testing sessions at a variety of loads
  4. to determine the accuracy of the ML program to predict 1-RM values
  5. to determine the validity of the ML software, compared with the motion capture software, to measure power

The investigators hypothesized that average power measured using the ML would be valid and reliable and that the greatest average power would be produced during lifts at 50% of the subject's 1-RM. Investigators also hypothesized that the 1-RM calculations provided by the device's software would be accurate within 5-7%.

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Amonette WE, Casperson S, Bentley J, DeWitt JK, Garcia Y, Guilliams MA, Twine CA, Edwards B, Mockus D, Hagan RD. Evaluation of the MuscleLab power testing system using bench press and leg press exercise. Houston TX: National Aeronautics and Space Administration, Lyndon B. Johnson Space Center; 2003 December. NASA Report.

Musculoskeletal physiology

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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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Average power on bench press
Average power on leg press
One repetition max

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
ROI 01/01/2002 12/31/2012 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)
Alternate Experiment Name