Defining soldier equipment trade space: load effects on combat marksmanship and perception–action coupling

Abstract

Soldier equipment compromises task performance as temporal constraints during critical situations and load increase inertial and interactive forces during movement. Methods are necessary to optimise equipment that relate task performance to underlying coordination and perception–action coupling. Employing ecological task analysis and methods from dynamical systems theory, equipment load and coordination was examined during two sub-tasks embedded in combat performance, threat discrimination and dynamic marksmanship. Perception–action coupling was degraded with load during threat discrimination, leading to delays in functional reaction time. Reduced speed and accuracy during dynamic marksmanship under load was related to disrupted segmental coordination and adaptability during postural transitions between targets. These results show how reduced performance under load relates to coordination changes and perception–action coupling. These changes in functional capability are directly related to soldier survivability in combat. The methods employed may aid equipment design towards more optimised performance by modifying equipment or its distribution on humans.

Abstract

Practitioner Summary: The combat equipment necessary for soldier survival and mission accomplishment significantly impedes task performance. Understanding relations among equipment, task performance, situational awareness and segmental coordination is necessary to define the trade space for design optimisation. This article begins to define this trade space in terms of perception–action coupling and survivability in combat.

Keywords::

• military ergonomics
• marksmanship
• perception–action coupling
• coordination dynamics
• survivability

Acknowledgements

This effort was supported by the U.S. Army Long Term Training program and the Office of Naval Research. The authors would like to thank the participants of the study for their contribution to this research during a period when they had very little time to give.

Notes

The views, opinions and/or findings contained in this report are those of the authors and should not be construed as official Department of Army position, policy or decision, unless so designated by other official documentation.