In the jiu jitsu community no two words can strike fear into a room quite like "knee reaping". The simple placement of one leg in a position of leg entanglement has been declared worthy of an immediate disqualification in many jiu jitsu competitions.
The rationale is simple enough, that it puts dangerous pressure on the knee of the trapped leg. Debates rage around the position and much of the perceived danger of the position comes just from the fact that is a banned technique. Ryan Hall, an accomplished black belt in competition and noted leg locker, has spoken on how fear of the position has been spread to the point where he has to explain to be people in his gym that the position is not nearly as dangerous as commonly thought.
This article will seek to demystify the position of the knee reap in an effort to make it less intimidating.
What is a knee reap?
The knee reap, as defined by the rules of the IBJJF, is "when one of the athletes places his thigh behind the leg of his opponent and passes his calf on top of the opponent's body above the knee, placing his foot beyond the vertical midline of the opponent's body and applying pressure on his opponent's knee from the outside."
Since that is somewhat of an opaque wording here is one of the images the rule book uses as visual aid:
As you can see a knee reap is occurring when the grappler in the white gi is controlling the grappler in the blue gi's leg and then brings the outside leg around and over blue's leg. But, in terms of using a knee reap these positions are fairly mild.
Here is an image of Reilly Bodycomb from his "No Kurtka" series using a very deep reap. Notice how Bodycomb has slid off to an angle in order to weave his right leg over the left leg and under the right leg of his student.
Can a reap hurt you?
The positioning of the legs itself will not injure your knee. However, the reaction of the person in the reap matters a great deal. There are situations that can result in injury. Attempts to kick the leg straight to defend against an ankle lock, known as ‘putting on the boot', can result in pressure on the knee and even injury. This can be compounded by the reaper straightening his own leg against the side of the knee. The position itself isn't dangerous, but the control it provides over the leg can lead to injury if some reacts to with an unschooled and explosive movement. Reaps can put uncomfortable levels of pressure on a tense knee, but relaxing the leg in the reap causes that pressure to alleviate.
Why use a reap?
The reap provides control of an opponent, particularly useful control when pursuing leglocks. Let's take a quick look at some of the controls reaping provides.
In this example white gi has his left leg reaping across the right leg of blue gi. You can see the tight squeeze of white gi's knees here. That's one thing the leg positioning of the reap allows for. One of the very basic keys of attacking with a leg lock is the tight control the fighter in the white gi is keeping on blue gi's knee. This control is maintained by keeping the knees below the knee of the blue gi fighter and keeping blue gi's knee pointed in the same direction as his own knees. The leg positioning of the knee reap allows white gi to get a very tight squeeze with both of his thighs, providing excellent control over blue gi's knee.
Other forms of the knee reap can play into more intricate forms of leg control.
Here is Stephen Koepfer, Head of the American Sambo Association and owner of New York Combat Sambo, demonstrating a leg entanglement on Rolled Up host Budo Jake. Notice how Stephen's right leg goes over Jake's left leg and then hooks under Jake's right leg. The purpose of this reap is both to control the direction Jake's knee is able to point and to control Jake's ability to roll, setting up both an ankle lock and a heel hook for Stephen. Additionally Stephen's left shin has come under the hamstring of Jake's left leg. The result is that Stephen is able to assert squeezing control on the trapped leg.
For a quick live action example here is a gif of Denny Lenormand, a student of Reilly Bodycomb, attacking a leg in a NAGA event match.
Notice how Denny establishes a knee reap very early and uses it to control his opponent's movement. His opponent tries to turn out of the leg lock, but Denny's reap allows him to maintain control of the trapped leg and his position relative to his opponent never actually changes despite all the movement.
In short, the properly applied reap provides optimal control of a leg for submission attacks in a variety of different situations but is not, in itself, a joint attack.
Are knee reaps unbeatable?
No, knee reaps are not a magical position that make leg locks impossible to escape. Different leg locks require different escapes and the reap often simply calls for another step: removing the control it provides.
Here is an outstanding example of one such escape by Reilly Bodycomb, note how the escapes are similar but the one with the reaping leg and outside leg control requires an additional step.
What are some additional resources on knee reaping?
The more you learn about the knee reap the less threatening it will be, so where can you go to learn from the experts? Here are a few suggestions, enjoy delving into the intricacies of this position and, hopefully, purging the fear of this misunderstood position.
Reilly Bodycomb's No Kurtka series, specifically Volume 2, is one of the more complete instructions on leg locks. A sample chapter has already been included, but here is the official trailer.
Stephen Koepfer has put out some excellent videos on reaping leg locks, so be sure to check out his YouTube channel. Here is an episode of the Budo Videos series Rolled Up feature Stephen which includes some excellent use of knee reaping to set up ankle lock controls.
Vladislav Koulikov is one of the very best Sambo coaches that has come to the United States and has been very involved in the East Coast jiu jitsu scene for years. Vlad has spent a great deal of time mixing the mindsets of Sambo and jiu jitsu. He has put out a great deal of material through BudoVideos. Here is a video he has put out for a taste of his coaching style.