was to characterize the effects of long-duration spaceflight on astronaut locomotor control and
functional mobility. The Mobility investigation was conducted with 18 ISS crew members over
the course of Expeditions 5-12. Locomotor function was assessed before and after spaceflight
using 2 tests of gait function. The first test characterized alterations in several systems
responsible for the control of locomotion. For this test,
subjects walked on a treadmill to assess changes in
dynamic visual acuity and lower limb coordination
strategies. The second test provided a corresponding
assessment of overall functional mobility by testing the
subjects’ ability to negotiate a complex obstacle course.
Toe clearance (minimum height of the toe as the foot
swings forward) during treadmill walking was assessed
to determine whether astronauts are at an increased
risk of tripping after their return from long-duration
spaceflight. Test performed on landing day showed
reduced toe clearance and an increased risk of tripping
during walking one day after spaceflight. However,
tripping risk on subsequent days was not different than
preflight (Miller 2010). Postflight changes in gaze
control produced decreases in the ability to see clearly
during walking. Recovery in visual performance
occurred during the 2-week postflight recovery period
(Peters 2011). Results from the obstacle course
indicated adaptation to spaceflight led to a 48%
increase in time to traverse the course one day after
landing, and recovery of function took an average of 15
days to return to within 95% of their preflight level of
performance. This recovery was characterized by a 2-
stage re-adaptation process characterized by a fast
learning response using cognitive supervision followed
by a slower learning process designed to ultimately
automate re-learned gait patterns (Mulavara 2010).
This research provides valuable data on the extent of postflight locomotor dysfunction, the rate
of improvement, and the expected duration of dysfunction of crew members following long-
duration spaceflight. These findings will be important in the design of interventions to reduce
or eliminate spaceflight related locomotor disturbances.
PUBLICATION(S)
Cohen HS, Kimball KT, Mulavara AP, Bloomberg JJ, Paloski WH. Posturography and locomotor
tests of dynamic balance after long-duration spaceflight. Journal of Vestibular Research. January
1, 2012; 22(4):191-196. doi: 10.3233/VES-2012-0456.
ISS010E24001 – Astronaut Leroy
Chiao, Expedition 10 commander and
NASA International Space Station (ISS)
science officer, equipped with a bungee
harness, exercises on the Treadmill
Vibration Isolation System (TVIS) in the
Zvezda Service Module of the ISS.
Crew members completing standard
exercise protocols on ISS are the
experimental controls for the Mobility
experiment.