Effects of Physical Impairment on Grenade Throwing and Weapon Loading Tasks

Abstract : Physical impairment of a Soldier during a mission will inevitably change the Soldier's ability to perform various mission-essential tasks. This study examined the effects of an artificially impaired hand and arm on grenade throwing and weapon loading performance. The grenade task examined distance and accuracy while throwing a grenade from the kneeling, standing, and supine positions, with and without physical impairment. The weapon loading task examined time to change a magazine on an already loaded weapon as well as loading an unloaded weapon under conditions with and without physical impairment. The grenade throwing distance data revealed (for each of the throwing postures) a significant main effect for the physical impairment condition (p less than 0.01, differences of up to 46 inches). There were no significant effects or interactions of the physical impairment condition relative to mean accuracy in any of the throwing conditions. Also, main effects for physical impairment were found for mean times to complete individual subtasks in throwing the grenade (i.e., pull grenade from pouch, pull pin, and throw grenade). In both weapon loading tasks, a main effect of physical impairment was revealed (p less than 0.01). The results of this study will be used to verify and validate capability requirements used in human performance modeling for grenade throws and weapon loading under conditions of physical impairment.