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Research to Watch | Curb-Sitting: Evidence-based Tactic or Illusion of Safety?

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Curb-Sitting

“Do me a favor and have a seat on the curb until we figure this out.”

Undoubtedly, many of you have either given or heard some version of this direction. The belief being that suspects sitting on the curb will have reduced mobility and thereby pose less of a threat than suspects left standing.

Although critics of curb-sitting have argued that the tactic is demeaning and unnecessary, it is defended as a reasonable de-escalation option, one that reduces a suspect’s opportunity to commit assaults.

Proponents of curb-sitting and other subject control tactics might point to the U.S. Supreme Court, which has repeatedly observed that, during detentions or arrests that may give rise to sudden violence, the risk of harm to both the police and the community is minimized if officers exercise unquestioned command of the situation.1

For police and community safety, curb-sitting theoretically makes sense. The question is whether curb-sitting provides police with an effective officer-safety tactic, or does it merely create an illusion of safety?

In our recent study, ‘Curb sitting’: An evidence-based policing practice or an officer safety myth? Joel Suss, Duane Wolfe, Güler Arsal, and I set out to test this theory.

Standing vs. 3 Seated Positions: The Study

In our study, we asked four questions:

  1. Are subjects sitting on a curb with their legs extended2 slower to get up and sprint 5 feet than when sitting with their knees bent and ankles crossed (i.e., yoga “Lotus style”)?
  2. Are subjects sitting on a curb with their legs extended and ankles crossed slower to get up and sprint 5 feet than when sitting with their legs extended but with their ankles uncrossed?
  3. How fast can a standing subject sprint across distances of 3, 4, 5, and 6 feet?
  4. Based on our research, does curb-sitting result in more response time than allowing subjects to stand?

Extended or Bent Legs: Did it Matter?

When subjects began seated with their knees bent and ankles crossed, they were on average .07 s faster to get up and sprint 5 feet than when they sat with their legs extended.

Whether the extended leg subjects crossed their ankles or not made no practical difference in their sprint times. The times reflected in Table 1 show just how close these trials were (M = mean or “average” / SD = standard deviation).

Table 1
Table 1. Means and standard deviations for response time (in seconds) by leg position and trial number.

Sitting or Standing: Who was Faster?

In our study, we also tested how long it took standing participants to cross distances of 3, 4, 5, and 6 feet (See Table 2). Notably, we found that each additional foot of distance resulted in a statistically significant increase in time.

Table 2
Table 2

As readers may have guessed, participants starting from a seated position required more time to cross 5 feet than those starting in a standing position. In all cases, subjects seated with legs extended (both crossed and uncrossed) averaged 1.355 s to cross 5 feet, while those who started from a standing position averaged only 1.096 s.

So, for officers standing 5 ft from a suspect, curb-sitting offers a potential response time advantage of a quarter of a second (.25 s). The question is whether our “statistically relevant” research findings translate to a real-world officer-safety advantage. Let’s discuss why that may not be the case.

Making Sense of an Extra Quarter Second

This study only begins the conversation on curb-sitting tactics, and we recommend the results be evaluated with care. Readers of this study should be clear on our findings.

First, the time benefit between having a person sitting “Lotus style,” compared to extending their legs, averaged less than 100 milliseconds (0.07 s). Whatever advantage you might imagine, that is far less time than it takes to blink.

Second, the time to cross 5 feet from a seated/legs extended position is about 250 milliseconds (0.259 s) slower than standing. Again, blink, and you may extinguish any perceived advantage.

Although “statistically significant” findings are important in the research context, it would be inappropriate for readers to walk away believing curb-sitting is sufficient for officer safety. More research is needed to measure curb-sitting variants before they can be compared to what we know about officer response times (e.g., would sitting on a flat surface rather than a curb further impede mobility?).

In the meantime, as we plan for future research, we can use this time to evaluate our study in the context of past related research.

Comparing Research

Force Science students and regular readers likely noted the time differences between our study and other research on sprint times. In The influence of start position, initial step type, and usage of a focal point on sprinting performance (“the Sprint Study”), researchers found that participants with a forward focal point sprinted approximately 3 and 7 feet in an average of 0.31 s and 0.59 s respectively. These times are much faster than our findings across similar distances (Table 2).

The slower times in our most recent study are likely based on the different procedures used by the participants.

In our study, participants began at the sound of an audible stimulus, whereas the Sprint Study used a self-initiated start. Using an audible signal meant our times would have included the perception and reaction times of the participants. It may be useful for future research to include self-initiated starts from various curb-sitting positions. This simple modification may allow findings to be further generalized to real-world conditions.

Another difference between studies is that the Sprint Study participants sprinted through the finish line (i.e., consistent with a suspect intent on fleeing). In our study, we had participants strike a pad on a table, which resulted in first slowing or stopping. Our research method was intended to represent the timing of a specific type of assault (i.e., no incentive to sprint past the officer). Consequently, it resulted in a notably slower sprint time than those subjects running through the finish line.

Conclusion

Law enforcement continues to focus on the safety benefits of time, distance, shielding (i.e., cover, barriers, concealment), and de-escalation. However, little empirical evidence guides us on how much time is necessary to create an adequate reactionary gap. At this point, we can only say that curb-sitting provides more time – but not necessarily enough time.

Anecdotal evidence has been the foundation of policing tactics, techniques, and training for decades. Certainly, the lives of many officers and community members have been saved by stewarding the most effective and often hard-learned lessons from generation to generation.

Of course, researchers and other academics are eager to support policing with evidence-based tactics, and our communities and civic leaders increasingly demand that we do. I agree with Sandel et al.’s (2021) observation:

Little is known about how quickly and effectively an officer can respond to different types of threats; yet this is exactly the type of research that should inform public, court, and police perceptions of use of force events. Better understanding of these factors can help protect the police by helping them to understand and avoid dangerous situations. The public is also protected when police have a clear understanding of the dynamics of these situations and their actual response capabilities, resulting in better decisions about when force should be utilized and when it should not. (p. 1315)

As we progress in our research efforts, we expect future research on curb-sitting to involve naturalistic conditions (e.g., stress, self-initiated starts, visual movement cues). We look forward to testing the influence of offline movement by officers (forward, backward, lateral), the associated time to draw and accurately deploy tools (TASER, OC, baton, or handgun), and the time needed to execute empty-hand skills.

Let us know where you would like to see our research go and how we can help you identify and develop evidence-based field tactics for increased officer and community safety.  Suggestions and comments can be sent directly to the author below.

Contact Author

References

Blake, D., Suss, J., Wolfe, D., & Arsal, G. (2022). ‘Curb-sitting’: an evidence-based policing practice or an officer safety myth? Police Practice and Research. doi: 10.1080/15614263.2022.2057982

Blake, D., & Bartel, L. (2018). Holster and handgun: Does equipment affect response time? Law Enforcement Executive Forum. 18(2).

Dysterheft, J.L., Lewinski, W.J. Seefeldt, D.A., & Pettitt, R. (2013). The influence of start position, initial step type, and usage of a focal point on sprinting performance. International Journal of Exercise Science. 6(4).

Sandel, W.L., Martaindale, M.H., & Blair, J.P. (2021). A scientific examination of the 21-foot rule. Police Practice and Research. 22(3). https://doi.org/10.1080/15614263.2020.1772785

  1. See Brendlin v. California, 127 S. Ct. 2400 (2007) (citing Michigan v. Summers, 452 U. S. 692 (1981 []
  2. For this question, feet extended could include either ankles crossed, or ankles uncrossed. []
9 Responses
  1. Chris Hall

    What interesting research! And a very good lesson in the difference between statistical significance and the real world implications. Nicely done

  2. Mike

    I’m curious about the direction of travel the person sitting on the curb was instructed to take after standing. Having them sit on the curb might only buy a reaction time of .25 seconds but that seems to be only if you’re standing directly in front of them (at their 12 o’clock position). I’d wager that time increases if you’re standing at the detainee’s 4,5, or 6 o’clock. Or was that part of the experiment that I missed?

    Standing behind the detainees might give them a bigger head start if escape is their plan. But in the current environment, officer survival (in every interpretation of that phrase) might take priority over suspect apprehension.

  3. Chris Leblanc

    I would have assumed a greater advantage than demonstrated in the research so looking forward to seeing more. Maybe a test where a suspect actually tackles an officer on rising.

  4. Ransom Carter

    A very interesting and thought provoking article. Intuitively, one would assume that the officer would have so much more time to react to the “subject” getting up from the curb. Another factor to consider in the speed of the “subject” rising from a seated curb position to a sprint is the flexibility of the “subject.” A “subject” who is flexible will be able to regain their feet faster than a less flexible “subject.” I don’t know how this would be tested and more importantly, I don’t know how the officer would be able to look at a subject and make that determination. Body type may be closely related to the flexibility factor in regards to the speed of the subject moving from sitting on the curb to sprinting. A thinner body would be more compact and efficient, one would assume, than a bulkier body type.

  5. While this research does make sense & has some value, perhaps it should have also included some measurement of the officer’s “reaction time” to the three different “curb sitting” vs. standing positions. In the martial arts, specifically traditional jujitsu for self-defense, we look at this time lag of .3-.7 seconds between the mind recognizing a danger/attack and starting to respond to the situation. In a street situation this “time lag” can be critical to effectively defending oneself, or in the case of law enforcement, reestablishing control over the detainee. Admittedly the officer[s] may be distracted by other factors that could easily increase their reaction time. So maybe there should be a similar study dealing with officer reaction time to the stated situations.
    My goal here is not to criticize as the above study has value, but to raise the possibility of a more comprehensive study which would cover the total situation.

  6. In response to comments so far – I certainly agree. I want to say that in my opinion, the study results should not dissuade agencies, trainers, or officers from using the curb-sitting tactic. We tested very specific parameters (i.e., straightforward movement) and therefore the results should be interpreted cautiously based on the limitations of the methods used. While more testing needs to be done – whether experimentally or naturalistically in the field (training) – the results simply suggest that officers should not become complacent or consider a curb-sitting individual as no longer a threat.

    We only tested the suspect time – which included their time to react to an audible stimulus. We did not test the time it takes an officer to visually perceive the attack and either move offline or otherwise defend themselves. These and other variables should be tested in the future. For instance, how long does it take an officer to perceive the threat from a curb-sitting suspect and successfully deploy a defensive weapon (TASER, OC, etc)? What benefits does moving offline (back/left/right) provide? Do certain visual cues from a seated suspect (i.e., uncrossing ankles) provide additional time for the officer to respond versus a standing suspect attack? There is so much more that needs to be evaluated.

    As a peace officer – I used this tactic successfully for years. I found it provided information as to whether the subject was going to be compliant or not and would adjust accordingly. I also believed it exponentially increased the overall safety of the encounter. However, my career was ended due to an attack from a curb-sitting subject who I attempted to handcuff from behind (not tested). The tactic did not provide me with the ability to respond to the attack in the way I thought it would. It literally happened in the blink of an eye! Therefore I was caught off guard by a double leg takedown (causing a spiral fracture).

    If anything – my hopes are that these results will prompt agency trainers to spend some time testing variables to determine what works in the field. We should not rely on “the way we’ve always done it” when it comes to officer safety tactics. In the original study, we recommended that in conjunction with the use of the curb-sitting tactic – officers should consider substantially increasing their distance (when possible) and having a barrier (cover) between themselves and the suspect. Bottom line – start the conversation – test your tactical theories – continuously evaluate their outcomes when used in the field – modify as needed. Be Safe! – Dave Blake

  7. bob hunt

    This and other research like it is useful training material. What would be even more useful is getting this type of research in front of a broader audience. There are still a few “reality” television shows like “Cops”. Perhaps Force Science could offer a few short videos of response time experiments to those shows.

  8. Eric Huesman

    Important to realize this study only compared the differences of seated vs. standing in regards to a straight sprint. In my experience, the primary advantage of having suspects sit on the curb is that it is much easier to control their movement while you are multi-tasking (watching the suspects while running their names, etc.). It’s very helpful in preventing suspects from triangulating the officer, and keeping all suspects in one confined field of view. That said, I also don’t think the quarter of a second slower sprint of a seated suspect is anything to be so easily dismissed. Force Science has done a lot research showing exactly how much can happen in a quarter of second, so why try to state it’s a negligible amount of time now?

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