One is ballistic cutting where the blade is in motion before it makes contact, the other is pressure cutting where you basically place the blade, get your accuracy, and then you can cut with a lot more force with a smaller knife.

eJournal: Does pressure cutting work under highly dynamic situations with everybody moving?Quads-wb

Janich: Yes. What you do is you control the arm first. You’d trap the arm and control it, limit the mobility to one joint, and then cut the bicep. But the real stopping target for us is the quadriceps muscle, just above the knee, about the first six inches.

eJournal: Why is the quadriceps an important target?

Janich: The mobility kill. Historically, look at the use of the medieval sword and shield. One of the tactics was to clash shields, because it was easier to lift the other guy’s shield so you could cut him across the quadriceps. Look at the records from early medieval battles where historians went back and excavated many of the graves of the people that fought there. The skeletons have deep, deep grooves where they had suffered those cuts across the quadriceps.

The quadriceps is analogous to the triceps; it extends the joint. The knee is a hinge joint and when the quadriceps contracts, it extends the knee and allows the leg to straighten and to support weight. You would cut the quadriceps, especially in those first few inches above the knee where it narrows. If you go higher on the leg it becomes very wide, so it is hard for a small knife to be effective.

Also, think about this: if you have a jacket, where will it hang down? Somewhere along the upper thigh. All the keys and coins and what ever else you happen to have in the pocket essentially acts like armor against the knife. In the first six inches or so above the knee, there is typically only a single layer of cloth (unless he’s wearing Carhartts) that is stretched tight across the knee in any kind of an athletic posture. You are cutting one layer of material and cutting muscle that essentially is going to drop him like a rock.

eJournal: That addresses proximity concerns about self defense with contact weapons. The quadriceps cut even seems like something mere mortals could accomplish, unlike some of the complex maneuvers we sometimes find in martial arts.

Janich: A few years ago at SHOT Show, a lady and gentleman–they are both paramedics and paramedic trainers by trade–came up to me in the Spyderco knife booth and said, “We can’t thank you enough for your videos, we really appreciate all the information.” So I said thank you for your kind words, and as I shook her hand she wouldn’t let go, so I thought, there is something going on here. She said, “You saved my life.” She had been raped, the evidence was screwed up and the attacker went free and continued to stalk her. She moved out of state, but he tracked her down, and attacked her a second time and separated her shoulder.