Motor performance and motor learning in sustained +3 Gz acceleration

Area of Science:

• Human Physiology
• Aerospace Medicine
• Motor Control

Background:

• Increased head-to-foot acceleration (+Gz), common in aircraft maneuvers, is known to degrade motor performance.
• Limited research details specific motor deficits (mechanical, timing, accuracy) or motor learning effects under +Gz conditions.

Purpose of the Study:

• To determine if mechanical function, timing, or accuracy deficits explain tracking impairments during +Gz exposure.
• To investigate whether +Gz affects motor learning processes.

Main Methods:

• A Test Group (N=10) performed manual tracking tasks under normal gravity (1 G) and +3 Gz, with subsequent left-right cursor feedback reversal.
• A Control Group (N=10) and a Weight Group (N=12) performed similar tasks at 1 G, with the Weight Group experiencing simulated +3 Gz load via arm weighting.

Main Results:

• Tracking performance decreased by approximately 50% at +3 Gz compared to 1 G.
• The impairment was partially attributed to non-mechanical factors, as the Weight Group showed only a 25% performance decrease.
• Tracking accuracy was significantly impaired at +3 Gz, while motor timing remained unaffected. Motor learning occurred similarly across all groups.

Conclusions:

• Tracking deficits under +3 Gz are likely due to impacts on accuracy from vestibulo-spinal influences or environmental stress, rather than purely mechanical or timing issues.
• +Gz exposure does not appear to hinder the fundamental process of motor learning.