First, let’s look at how quickly some basic knife attacks take to execute. Based on FSI edged weapons research, at arm’s length a knife thrust can be completed in 0.10 seconds, a pick style attack in 0.18 seconds, a palmed blade in 0.23 seconds, and a butterfly in 0.33 seconds. In the clearest setting, when you know an action is going to occur, it takes about 0.25 seconds to perceive and start a response to visual stimuli. Add in factors such as a startle-flinch response, shifts in attention or focus, and those times can double or quadruple quite easily. For more perspective, a blink of the eye is around 0.33 seconds. What does this mean? At arm’s length, if you missed context cues and/or pre-attack indicators, common knife attack moves can be completed before you can even observe and start your response to them. In any ambush, but especially in close-quarter
ambushes,
situational awareness must be your first line of defense. Not merely just keeping your eyes peeled, but observing with intent, and understanding what to look for.
Applying Science to Movement
Hick’s Law tells us that by reducing our number of choices, we reduce the time it takes to make a decision. With the above data in mind, what can we begin to eliminate in training to help simplify our decision-making process?
Let’s start with directions of movement. Again, if these attacks can occur faster than observations can be made and faster than responses can be initiated at this distance, the last thing we want to do is step forward. Let me clarify, I’m not talking about sparring, dueling, or other fights where you already see the knife and the angle of attack based on other body movements. This conversation is specific to a rapid knife pull and attack in an ambush fashion. So, stepping forward with any sequence of defenses as an initial response is thereby off the table.
We can clean our defensive strategy up a bit more using additional data from Force Science Institute’s Sprint Start Study. Most of us understand you can’t move backward faster than someone else can move forward, but let’s put some numbers down to help solidify this. In six strides backward, you only cover approximately 14.94 feet in 1.56 seconds. In six strides forward, you can cover approximately 25.72 feet in 1.67 seconds. The average person can cover nearly two-thirds more distance forward as the average person moving backward in the same allotted time. It’s also important to note that these times are slower when adding duty boots and
duty equipment
into the equation. Additionally, if you review video footage of anyone attempting to retreat backward in response to a threat, often the person becomes a victim of gravity and ends up on their butt.
So, how do lateral steps fair in comparison to forward movement? Almost identical out to the sixth stride. The average person can move 24.98 feet in six left strides, in 1.64 seconds, and 24.98 feet in six right strides, in 1.65 seconds. Moving left and right in a rapidly unfolding situation is almost exactly as fast as moving forward. It also gets you off the “X,” perhaps allowing you to step off the attacker’s radar, as attackers can experience tunnel vision as well. In addition it slows the attacker’s movement toward you, as it forces an angle change to reacquire you. And with the initial step laterally, you are still in range to observe what’s taking place and decide whether to physically re-engage the attacker or continue moving away.