Locomotor function after long-duration space flight: effects and motor learning during recovery

Area of Science:

• Space Medicine
• Human Physiology
• Motor Control

Background:

• Astronauts adapt to microgravity, leading to sensorimotor changes.
• Transitioning back to Earth's gravity (1-g) presents significant challenges for astronauts.

Purpose of the Study:

• To assess locomotor dysfunction and recovery post-long-duration space flight.
• To investigate the role of early motor learning in re-adaptation to Earth's gravity.

Main Methods:

• Eighteen International Space Station crewmembers performed a functional mobility test (FMT) pre- and post-flight.
• The FMT involved walking an obstacle course on foam, measuring time to complete the course (TCC).
• Multilevel exponential recovery models analyzed TCC data for long-term recovery and early motor learning.

Main Results:

• All astronauts showed altered locomotor function, with a median 48% increase in TCC post-flight.
• A typical subject was predicted to recover 95% of pre-flight function by 15 days post-flight.
• Significant positive correlation found between long-term recovery and early motor learning.

Conclusions:

• Two recovery processes are crucial for astronauts re-adapting to Earth's gravity.
• Early motor learning facilitates rapid adjustments in motor control strategies shortly after landing.
• Early motor learning reinforces adaptive realignment, aiding re-adaptation to 1-g environments.