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Abhilash Pandya
05-22-1998, 07:11 AM
Hello Biomch-l,

Our group at NASA/JSC is tasked to study and model fatigue of all major joints
of a presurized space-suited astronaut. We would also like to compare this
data with his/her unsuited fatigue. We have a dynamometer that can be run in
isotonic, isometric and isokinetic modes and collect data from all joints of
interest. We cannot collect EMG on the subjects because of the suit. We would
like the collected data to reflect and generalize to on-orbit type tasks.

We have several question for the group:

1. What modes of data collection (isotonic, isokinetic or isometric) and in
what combinations is it advisable to study fatigue?

2. Most of the actions in space are of the isotonic nature. Has anyone looked
into how to collect isotonic fatigue data? Our main concern is with limiting
the range of motion due to the subject's inability to exert sufficient torque
to overcome the resistance near the extreme angles. Also, there is concern
about the speed at which the isotonic motions should be performed.

3. Rather than performing explicit isotonic tasks, would it be sound to
extrapolate data from isometric and isokinetic testing? Has anybody done this
before?

4. Does anyone know a rule-of-thumb for recovery times for isokinetic or
isometric contractions in general, regardless of muscle group, or is this
unattainable? Schwender et. al. tested subjects performing fatiguing
contractions of the quadriceps femoris, and found that subjects fell into three
different groups of fatigue/recovery profiles. For the group of subjects that
fatigued the most, eight minutes may not have been enough time to
recover (here recovery was defined as being able to achieve >=80% MVC
over 2 consecutive contractions). Has anyone else performed similar
work on different muscle groups?

Assistance on any of these questions would be very helpful. A summary of the
results of this query will be posted.

Thanks in advance.

Abhilash.

--
Abhilash Pandya /C44 (281)483-3728 pandya@graf6.jsc.nasa.gov.
2400 NASA RD. 1 * Houston, Tx. * 77058-3799
http://www-sa.jsc.nasa.gov/FCSD/CrewStationBranch/GRAF/GRAF_Home.html
Study without action is futile. Action without study is fatal.-- Unknown.

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