Veteran police officer and law enforcement trainer Bruce Siddle took the stage at TREXPO East in late August and proceeded to confuse his audience. For the first few moments of his presentation on the body's reaction to combat, Siddle gave a quick lecture on the ancient Peloponnesian War battle of Delium. Some of the hundreds of cops, feds, deputies, and soldiers in the audience must have wondered if they had somehow stumbled into a classical history course. But Siddle brought it all together over the breadth of his two-hour presentation on use-of-force human factors.

Siddle opened with a discourse on Delium because he wanted to show how failure to understand the body's reaction to combat can lead to disaster. In the case of Delium, ancient Athenian soldiers confused in their battle against the Boetians started slashing their own comrades. It was history's first recorded case of "friendly fire."

What can today's cop learn from the misfortune of ancient Greek infantry? Plenty, according to Siddle who went on to give other examples of erratic behavior under fire, including the documented fact that numerous rifles recovered after the battle of Gettysburg were still loaded and many were loaded multiple times.

Siddle has spent much of his professional career researching what the average officer or soldier might refer to as being "scared spitless." His work on the sympathetic nervous system has revealed some intriguing insight into why some people can work through combat fear and some can't.

In his book, "Sharpening the Warrior's Edge," Siddle explained that many warriors fail in their mission and suffer calamity because they do not understand how combat stress and fear affect their performance. At TREXPO East he expanded that argument into a discussion of training and its role in combat performance. Police trainers who do not have a grasp of the human element of combat and the physiological stress that it places on the body often set up their officers for failure, Siddle said.

Maintaining proper nutrition and hydration can also help reduce the influence of fear on the body, Siddle says. "Fatigue leads to fear, and fear leads to the triggering of the sympathetic nervous system (SNS)," he explained.

The SNS—often called the "fight or flight circuit"—causes the heart to race, blood pressure to rise, and other physiological reactions intended to make a person fast, quick, and strong. However, these reactions are not always beneficial to a warrior and the body cannot maintain this state for very long.

Siddle explained the SNS response as the way you would feel if you were "walking through the woods, turned a corner, and came face to face with a grizzly bear. The SNS is the startle reflex that you experience in a life and death situation," he said.

The SNS has a variety of effects on a police officer in combat. For example, an officer experiencing an SNS response cannot focus on the front sights of his or her pistol. This is why Siddle recommends that officers train to respond with aimed fire and with combat point shooting. "If you have time and distance, then there is no SNS response and no startle," Siddle said, explaining that both aimed fire and point shooting have their place.

Siddle also explained that the SNS loop is the reason that some warriors become hypervigilant to the point of not being able to function in combat. For example, one police officer under fire performed three tactical reloads of his magazines without firing a shot. Hypervigilance is also the reason that a terrified soldier at Gettysburg somehow managed to ram 20 complete loads down his muzzle loader but never fired a shot.

According to Siddle, the best way to reduce the chance of being startled in combat and experiencing an SNS response is to have the mindset of a predator, meaning a natural predator like a tiger. "The tiger is mission-driven, it exhibits quiet confidence, it is highly aware of its situation at all times, and it acts with controlled aggression." He went on to explain that these attributes can make a warrior less likely to be startled by sudden combat. For example, being situationally aware increases the time and distance between you and the threat, making it easier for you to effectively respond and minimizing fear.

Closing his presentation, Siddle said it was critical for police trainers to take a more holistic approach to combat training. "We need to look at all of the intangibles of human response and bring them together in our training." He also argued for combining fitness, use-of-force training, close-quarter combat training, and defensive tactics training into one discipline that is based on research into the physiological reaction of warriors to combat. "We need to avoid the flavor of the month," he added. "The flavor of the month kills and advanced techniques are really just the basics mastered."

He also had a final message for the TREXPO East audience: "I encourage you to take your profession seriously and to study combat human factors. Little things make a big difference in combat," he said as he left the stage to enthusiastic applause.

The second keynote speaker, Kelly McCann, is a self-professed Type-A personality. Known for his dynamic training videos portraying alter ego Jim Grover, the president of the Kroll Security Group always prefers action to inaction. But as he told attendees at his keynote address, in his years conducting military covert operations McCann learned that the "bull in a china shop" routine doesn't catch nearly as many bad guys as taking the time to use intel before conducting a raid.

It's no coincidence that "Brains and Muscle" was the title of McCann's joint keynote address with colleague Eric Weinberg. McCann believes adding sound intel to any law enforcement operation yields the best results.

Weinberg couldn't agree more. In his work with McCann researching effective counter-terrorism techniques at Kroll, he has found that by noting crime trends and subtle clues from minor crimes, cops are better able to uncover larger crimes in the making—maybe even the next terrorist bombing.

Because both terrorists and criminals are becoming more sophisticated, "The role of law enforcement is to educate yourself, stay abreast of events, enforce the law with vigilance, and be alert for evidence of terrorist activity," Weinberg told the audience.

But to be truly effective, officers on the street cannot operate in a vacuum. "Exchange of information is critical," he emphasized. This means communicating with others within an agency; at other city, county, and state agencies; and at the federal level.

Weinberg also encouraged attendees to be on the lookout for terrorism techniques being used against our troops in Iraq that might pop up in our own backyard. And reading texts such as the 9/11 Commission Report and "Jihad for Dummies" provides insight into terrorist operations and mindset, as well as the smaller predicate activity crimes such as identity theft or workers comp scams that can signify larger plans.

Weinberg urges all law enforcement officers to take anti-terrorism upon themselves by doing their homework and passing along information, even if it seems small.

"There is no pure terrorism case," said Weinberg. "There's a criminal predicate activity. You need to know what to look for."