Straining GOR tolerance determinations are a measure of G-duration not G-level tolerance

Area of Science:

• Physiology
• Aerospace Medicine
• Human Factors Engineering

Background:

• Gradual G onset rate (GOR) tolerance is traditionally used to assess G-level tolerance in aviators.
• Recent advancements in mathematical modeling allow for more sophisticated analysis of G-force exposure.

Purpose of the Study:

• To re-evaluate the validity of using straining GOR tolerance as a measure of G-level tolerance.
• To investigate the primary limiting factors of G-duration tolerance.

Main Methods:

• Utilized newly developed mathematical models for G-level and G-duration.
• Compared predicted G-level tolerance with measurements from subjects undergoing centrifuge testing using straining GOR protocols.

Main Results:

• Straining GOR tolerance appears to be a measure of G-duration tolerance, not G-level tolerance.
• G-duration tolerance is primarily limited by fatigue, not cardiovascular insufficiency.
• Mathematical models predicted higher G-level tolerances than observed in GOR testing, suggesting subjects did not exhaust their energy reserves.

Conclusions:

• The commonly used straining GOR profile (0.1 G/s) is not an accurate measure of G-level tolerance.
• Current fighter pilot selection standards based on G-level tolerance may be flawed.
• Accurate G tolerance profiles are crucial for evaluating the impact of equipment design changes on pilot safety.