What is Knee Reaping in Brazilian Jiu Jitsu?

Two people displaying a BJJ knee reaping

When learning Brazilian Jiu Jitsu, or simply trying to understand a UFC fight on TV, one can get lost in all the position names and bizarre jargon. Jiu Jitsu lingo like “Oss,”, “Porra,”, “Shrimping”, “Upa” and “knee reaping”. This can make you feel like you are learning an entirely new language (which, in a way, you are.)

What is knee reaping in Brazilian Jiu Jitsu? Reaping refers to the “knee reap” move. In a knee reap, a person who has his opponent in a foot lock swings his leg toward the opponent’s opposite side. The attacker then applies pressure on the opponent’s knees, causing the knee to bend inwards. It is illegal in beginning and intermediate level Jiu Jitsu competitions.

There is controversy within the Jiu Jitsu world regarding the knee reap. Most legitimate competitions do not allow the knee reap move. However, some competitions do

So, it is essential as a prospective Brazilian Jiu Jitsu athlete to know what a knee reap is to avoid disqualifying yourself or hurting your training partner. Just as important is knowing how to avoid being injured by one should your opponent use one on you.

Deconstructing the Knee Reap Position

A knee reap occurs when you have your opponent in a straight foot lock. The reap happens when your leg moves in the wrong direction.

While you are holding your opponent’s leg, your foot should never cross their body. For example, if you have grabbed the left leg, your legs must stay on your opponent’s left side. 

If you now sweep your foot to the right side of your opponent’s body, then you will start to bend their knee inward.  

The Brazilian Jiu Jitsu rule book has the following definition of knee reaping: 

 “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.” – IBJJF (Official Rules) (source)

If you want a slower, closer look at the move, this instructional video breaks down the positioning of the feared ‘Knee Reap’ in excellent detail.   

Is Knee Reaping Dangerous?

All moves in Brazilian Jiu Jitsu can be considered dangerous if not executed properly or surrendered to correctly. The knee reap is undoubtedly no exception.

A Brazilian Jiu Jitsu athlete’s goal is to subdue their opponent into submission by using technique and skill. If a fighter is put into a position which they truly cannot escape without sustaining an injury, they are taught to tap out.

While this means that fighter will have lost their round, it would also mean they might have avoided an injury that could damage serious enough that it might require surgery

The risk of injury involved when doing a knee reap depends entirely on the athletes in question.

If an attacker executes the move correctly (and mildly) and if their opponent taps out or succumbs to the position until they can think of a new plan of attack, then no injury is likely to occur.

However, when the knee is twisted inward with enough pressure, severe injury will more than likely occur.

In the case of the knee reap, the trapped fighter should not fight against the reap (try to twist out of it), as this is what will incur damages.

While counter-intuitive, a fighter trapped in a knee reap would want to surrender to their current position, even if it means potentially tapping out, as it is not worth shredding their knee ligaments.

However, there are still BJJ athletes who have attempted to ‘go with it’ and not fight against it, and even ended up having to receive knee surgery down the road.

Unfortunately, a lot of beginner Jiu Jitsu athletes who find themselves in a knee reap, don’t know that they are meant to tap out in this position (unless they know how to escape it safely, which is unlikely when first starting out.)

Since many beginner fighters are eager to best their rivals, a knee reap can easily cause severe and instant injury to an athlete only just starting out (which is precisely why it is not legal in most arenas.)

Is Reaping Legal?

Knee reaping is illegal in the IBJJF and the UAEJJF.

It is not allowed due to the perceived level of harm and injury that can (and does) occur to the knees when it is performed.

However, there are some competitions like ADCC and other such no-gi grappling tournaments that do allow knee reaping. That being said… it’s generally seen as ‘not cool’ to perform.

The United World Wrestling (UWW) competitions do permit the knee reap, and it isn’t seen as such a ‘no-no’ in this environment. These tournaments are not open to just anybody–national federations carefully pick expert athletes to represent their countries. 

Why Learn a Reap if You Can’t Perform It Legally?

You need to know how to perform a knee reap, and what it feels like to have one performed on you, for two reasons:

  1. So, You Don’t Get Disqualified – If you aren’t aware of what a knee reap is, and accidentally perform one in a competition, you could quickly get yourself disqualified. Since a lot of competitions, especially for beginner BJJ athletes, do not allow knee reaping, you need to know what one is to avoid the move.
  2. So You Know What to Do if it Happens to You – as mentioned previously, a knee reap can be dangerous and cause serious injury if an athlete does not know how to properly get out of the move and/or isn’t aware that they may have to surrender. All BJJ athletes should learn difficult and dangerous moves, not only to use on their opponents, but to know how to exit this move when applied safely. It’s not worth tearing your ACL over.

Are Knee Reaps Impossible to Escape?

No. Knee reaps are not impossible to escape. They are incredibly difficult to escape, though. Especially when trying to do so with zero amount of injury.

To overcome a knee reap, one must remove the control the reap is providing the attacker. Only truly skilled BJJ athletes know how to do this safely.

This video breaks down the knee reap and how to prevent injury when one’s knee is being reaped.

Why Execute a Knee Reap?

The goal of Jiu Jitsu is to conquer your opponent. If you are allowed to use the knee reap in a competition legally, it is a useful skill as it is incredibly difficult to escape (safely), and not every athlete knows how to escape it in the first place.

A truly skilled and powerful knee reap can lead to even the strongest athlete having to tap out. It’s like calling ‘checkmate’ in a game of chess.

The Key Take Away?

Reaping in Brazilian Jiu Jitsu is a handy tool when attempting to conquer one’s opponent.

However, it is (generally) banned from use due to the perceived level of danger it can cause to the knee. It is still wise for BJJ athletes to learn how to both perform and exit this hook-move. 

It’s a valuable tool to have in your fighting toolbox should you be allowed to use it. Also, it’s wise to know what it is and how to avoid it in competitions where it is illegal.

Likewise, it’s crucial to know what to do when forced into a knee reap to avoid serious damages to your knee. However, the general rule is to avoid performing a knee reap. Period.

There are so many other moves that can successfully subdue an opponent that it is not worth putting a fellow fighter at risk, unnecessarily (and illegally).


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