New Force Science Studies: The Stand Up Speed Of Proned-out Suspects, Plus The Impact Of Physical Exertion On Shooting Performance

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Some surprising findings are surfacing in the preliminary analyses of two new studies conducted by the Force Science Institute.

One study concerns the speed with which a suspect can scramble up from a proned-out position to a flight-or-fight stance. Results are showing that the time involved is far shorter than you may think, despite positioning tweaks that officers commonly believe will impede sudden threatening movement.
The other study explores the impact of exertion and stress on shooting performance. The surprise here relates to whether the physical drain of pursuing and grappling with a resistant suspect affects deadly force decision-making.

Research data are still being processed, but findings that may ultimately have training implications already are emerging.

Study 1: The speed to rise from prone to standing

Proning out a suspect is widely accepted by officers as a tactic that will buy them a reactionary edge in case the subject decides to launch an assault or attempt to flee. But how much of an edge does it really buy?

At an academy in the Midwest, a research team headed by Dr. John O’Neill, a behavioral scientist on the FSI staff, assembled a group of recruit volunteers to find out. The participants on average fit the physical characteristics of suspects who typically attack LEOs, as determined by an earlier study led by Dr. Anthony Pinizzotto, a former Force Science instructor: male, mid-20s in age, just under 6 ft. tall, and weighing about 175 lbs.


One at a time, 89 recruits acting as suspects were videotaped starting in two prone positions frequently seen on the street: 1) flat on their belly, hands tucked under their chest (a position that offenders may assume in direct defiance of officers’ positioning orders); 2) arms out to the side in a T position, palms up.

Then 66 of the same volunteers were tested starting in two additional prone positions: 3) arms out and legs crossed at the ankles; 4) arms out, ankles crossed, legs bent so the feet were angled back toward the butt.
As cameras rolled, each “suspect” was given the same simple command: “Stand up as fast as you can.”


“We were expecting to find a lot of variance” among the positions, O’Neill told Force Science News. But when the video footage was time-coded and analyzed frame by frame with the help of computer software that allows for measurements in milliseconds, “very surprising data” became clear.

“From all four positions flat on the ground,” O’Neill says, “the subjects rose up to standing in one second or less. They got up in different ways, but in no more than a second—faster than we expected—they were up with their hands off the ground and their body weight fully supported by their feet in kind of a crouch from which they could launch an aggressive move or start to escape.

“Across the four positions, the most extreme difference between the slowest time to rise and the fastest time was less than only two-tenths of a second. Usually the difference was less than one-tenth of a second.

Statistically, the suspects were able to rise up fastest from the position with hands tucked under their chests. The slowest was with feet bent back toward seat.

“From an analysis standpoint, these minuscule differences have some statistical significance,” O’Neill says, “but from a practical standpoint they appear essentially of no major consequence.”


“Our conclusion is that prone positioning, even with supposed hindrances like crossing the legs, is not as safe or as inhibiting to suspects as many officers believe,” O’Neill says. “A proned-out suspect still presents significant potential danger and officers should remain vigilant.”

While the research findings do not lend themselves to recommending a preferred method of prone positioning, O’Neill hopes that future experiments will lead to tactical improvements. “If readers have other variations they’d like to see tested, we’d welcome hearing from them,” he says.

Meanwhile, when the current results are finalized, we’ll be reporting on these tests in more detail.

Study 2: Exertion, stress, and the deadly force option

Like the study described above, this research project is believed to be the first of its kind.

Led by staff behavioral scientist Dr. Dawn O’Neill, a team from the Force Science Institute tracked 30 recruits as they maneuvered an integrated DT/firearms exercise developed and routinely used by trainers at the Kansas City (MO) PD’s Academy.


Wearing a chest heart monitor and full duty gear, each volunteer was told to jog outdoors in chilly weather for about 100 yards down a hill from a training building to conduct a “pedestrian check.” The recruit found a role player lying on the ground initially. But as the participant approached, the man bolted up and took off, tossing aside a baggie as he ran.

As the recruit pursued on foot “really fast” around three sides of the training building, he or she was suddenly intercepted by two of the suspect’s “buddies” intent on stopping the chase. One attacked, “realistically” grappling and maneuvering the recruit to the grass and fighting to seize his/her handcuffs and sidearm, requiring the dynamic application of DT and weapon retention techniques across a period of about four minutes. Ultimately, the recruit won and successfully handcuffed the adversary.

After a quick safety check, the participant was then promptly brought to an indoor range for a shooting-accuracy test under a low-light setting.
Earlier in their training, all the recruits had passed their firearms qualification tests. “Now from a distance of five yards, each was to fire 10 rounds within seven seconds at a turning target of a young male pointing a gun at them,” says O’Neill. “The goal was to hit a five- by seven-inch rectangle positioned at high center mass and ideally to hit even a small black square within that rectangle.”

Immediately following that, the recruit was thrust into a tense decision-making exercise. While tactically clearing a series of simulated alleyways said to potentially harbor hidden “hostiles,” the recruit was forced to react in fast sequence to nine turning targets, randomly presenting threats that warranted deadly force or benign images that should be no-shoots.

Finally, in a separate room, each trainee underwent a brief test of short-term memory. “This involved the ability to remember and repeat a spoken series of up to nine numbers both forward and backward,” O’Neill says.


Five days earlier, the recruits’ resting heart rates had been recorded in a non-stressful setting and they had been given the same shooting and memory tests under non-exertion conditions. “Their performance at that time became the ‘control’ against which we measured the effects of the intense physical activity of the grappling and foot chase,” O’Neill explains.

“Physiologically, we found a huge difference,” O’Neill says. “During the grappling phase, heart rates of all participants spiked up more than 100 beats per minute from the typical control reading, with one individual hitting 216 bpm.

“Besides the physical exertion, there was a lot of psychological stress involved, with the officer being alone, being attacked, being outnumbered, their weapon jeopardized, and so on. Most said they were ‘very exhausted’ physically and mentally after the fight.”

On the range, with heart rates still significantly elevated, “we saw evidence of a trade-off we believe resulted from their exhaustion,” O’Neill says. “They tended to shoot faster and fire more rounds than they had in their control tests—but they fired less accurately.” All the participants were able to place rounds on the targets 100% of the time—no misses. But significantly fewer rounds struck within the rectangle and the square, the intended ideal locations.

“This was not surprising to us,” O’Neill explains. “What was unexpected was the outcome of the shoot/don’t shoot decision-making tests.
“Essentially, we found no erosion in the percentage of correct decisions between the control scores and those registered after exertion. In both conditions, the recruits were correct in their choices more than 80% of the time.”

Some of the shoot/don’t shoot targets included photos of police officers in undercover clothing but displaying badges or other law enforcement identification instead of threatening weapons. These targets tended to draw the most significant number of judgment errors in both the control and exertion conditions, O’Neill reports.

Ironically, however, in these blue-on-blue confrontations, the recruits’ scores improved in addressing these targets when they were under the physiological and psychological stress of exertion, although the improvement still did not equate to “passing” scores for the majority of blue-on-blue targets, O’Neill says.

Another surprising finding concerned memory. As a group, the recruits’ ability to remember a spoken series of numbers did not change from control to exertion.


Currently, O’Neill and her team are “exploring the data more deeply” to better understand these outcomes and, hopefully, to offer practical “field implications” for improving officer training and performance.

“This study is breaking new ground on the relationship between physical exertion and shooting performance,” O’Neill says. “The only previous research on this topic that we’re aware of involved testing shooting proficiency after officers pedaled an exercise bike for 60 seconds—not at all comparable to measuring performance under realistic conditions.”
She commends KCPD trainers Sgt. Ward Smith, a certified Force Science Analyst, and Sgt. Kurt Schmidt for suggesting a study based on their exertion exercises, and Capt. Stephenie Price for her support of the research. O’Neill urges other trainers and officers with study proposals to contact the Force Science Institute.

Collaborating with FSI on this study was the Police Research Laboratory at Carleton University in Ottawa, Canada. The Lab provided two team members, Dr. Craig Bennell of the university’s psychology department, who served as the principal investigator, and Simon Baldwin, an Advanced Force Science Specialist who also works as a use-of-force data analyst for the Royal Canadian Mounted Police.

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