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Abstract

When law enforcement officers (LEOs) face the spontaneous acts lethal force, there is no “warning or foreperiod;” as in typical assessments of motor response, which rapidly evokes a startle response. The Firearms draw in controlled settings is; however, such an analysis when under duress has not been examined for motor response. PURPOSE: The purpose of the present study was to evaluate LEOs firearm draw and motor response following a spontaneous presentation of lethal force in a training scenario. METHODS: A total of 22 active duty LEOs engaged in training scenario under the ruse of a “communication experiment.” The officers were instructed to take the report from a woman that was struck by her husband. The first trial was terminated with a whistle below at approximately 1 min. In the second trial, a door in the back of the room slams and a husband enters the room yelling. When the husband entered the visual field of the LEO (~20 ft away), he drew and fired a training pistol armed with training ammunition at the LEO. The LEOs were video recorded (Go Pro) and their kinematics were measured using wearable sensors (OPAL). A third gun draw trial, not under duress, was recorded to act as a control. RESULTS: The threat of lethal force evoked a startle response of 0.78 ± 0.44 s with the most common startle responses characterized by shielding of the body with the non-shooting arm and flexion of the neck and/or back to “dodge” the gun shot. Initiation of the tactical response, i.e., moving to draw their weapon to return gun fire, occurred during the startle suggesting the startle is an open-loop motor program and the tactical responses is a close loop motor program. Draw times were 0.35 ± 0.29 s slower under duress vs. the control trial (t=3.40, p=0.003, d=1.05). The elbow kinematic profiles of the practice draw were observed being more efficient and faster, whereas the ambush draw displayed characteristics of over emphasizing each phase of the gun draw kinematic profile, causing the gun draw to take longer (r= -0.111, p=0.622). CONCLUSION: More dynamic environment training in ambush type situations is needed based on our findings that suggest no performance or kinematic efficiency carry over to the ambush trial compared to the practice draw, due to the novel observation of the startle response and firearm draw overlapping.

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