Quantifying Stress in Training

Data regarding the use of gun sights during a gun battle, indicated that only 30% of the officers reported being able to see their front sights, and only 25% used them.


We know the importance of training in police work as it relates to our survival. Anyone who is not familiar with the axiom, The way you train, is the way you fight, has probably been hiding underneath a rock somewhere in the mountains. Stress influences the way we react to situations on the street. What we as trainers need to understand, and subsequently structure our courses to combat, is to somehow replicate that stress, and train our officers to win, in spite of the deleterious effects that stress has on our performance.

In 1998, Bruce Siddle conducted research involving officers in an identical training scenario with various stressors included. There are not many studies of this kind, since controlling all of the variables and quantifying results is an enormous task. Nevertheless, Siddle embarked on this ground breaking journey, and titled the work, Combat Human Factors: Triggering the Survival Circuit.

In the study, he discussed a great many things, to include how we shoot. He compared and contrasted Isosceles and One Hand Point shooting, as they relate to close quarter combat. These two types of shooting styles were developed in the 1920s, the purpose of which was to promote quick response type shooting without using the sights. The two systems have been tested and refined since then, and have been proven to be highly effective techniques for survival. Interestingly, after Siddle's study was conducted of the officers involved in a stress-induced scenario, more than half resorted to an Isosceles/Modified Isosceles stance, i.e., squared up to the threat, even though the vast majority of the participants in the study were trained to shoot in the asymmetrical Weaver stance, which is a bladed technique.

In Siddle's research, his methodology included utilizing a PRISim Video-Based Judgment Simulator, with a ShootBack Cannon, installed in a trailer. Capable of firing a .68 caliber nylon ball at 120 feet per second, the officers' stress response was elevated, knowing the bad guy was actually able to shoot at them and hit them if they were not tactically sound. A single identical scenario was utilized for each officer, and a dispatcher was placed in the trailer to simulate real-time response and interaction. An air horn was sounded by a team member at a certain point during the scenario as well.

What distinguishes this work from others is that previous studies were never able to confirm whether survival stress had actually been induced, nor were researchers ever able to quantify the test subjects' actual performance against their perceived performance. Siddle therefore controlled as many environmental variables possible, and tracked physiological and cognitive changes as they occurred. He tracked heart rates, and by using blood samples, he measured changes in stress hormones and linked them to performance. He further had participants complete post-event surveys, and then compared them with real-time video playback of the subjects' performance.

The huge differentiator in Siddle's work is the blood analyses. It demonstrates, unequivocally, what happens to our Sympathetic Nervous System when we're exposed to a life-threatening event. A myriad of psycho-physiological effects occur, which include increased heart rate, adrenaline, and high levels of stress hormones, such as Cortisol, epinephrine, and norephinephrine. We also know that combat motor skills are affected, resulting in auditory exclusion and tunnel vision, to name just two. Siddle was joined by Dave Grossman in several studies involving combat-induced stress. The pair concluded that whenever a tremendous amount of stress is placed on the officer, there exists a huge potential for memory problems. They labeled this phenomenon, Critical Incident Amnesia. Siddle's research bears this out.

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