Gender and effect of impact acceleration on neck motion

Area of Science:

• Aerospace Medicine
• Biomechanics
• Human Factors Engineering

Background:

• Expanding research on female responses to G-forces is critical with women entering fighter cockpits.
• Women's potentially lower upper-body strength may affect head bracing during high G-loads and impact, increasing injury risk.
• Evolving helmet technology further complicates head-borne weight and center of gravity dynamics.

Purpose of the Study:

• To measure the capacity of both sexes to brace against impact acceleration (-6.5 Gx, +4.0 Gy).
• To explore correlations between bracing ability and static/anthropometric measurements.
• To identify predictors of head motion during acceleration events.

Main Methods:

• Subjects were exposed to controlled impact acceleration environments (-6.5 Gx and +4.0 Gy).
• Static strength and anthropometric measurements were recorded for each subject.
• Head motion amplitude was quantified and correlated with strength and anthropometric data.

Main Results:

• No correlation was found between static strength or anthropometry and head motion amplitude.
• Isometric strength correlated with body size and neck circumference, but did not predict head displacement.
• Pre-impact neck force showed a strong correlation with head motion in -Gx impacts and a moderate correlation in +Gy impacts.

Conclusions:

• Neck strength is a useful, albeit conditional, predictor of impact resistance.
• Motivation significantly influences the ability to brace against acceleration forces.
• Findings inform safety protocols and injury prevention strategies in high-G environments.