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What Is Knee Reaping? (Full Guide for BJJ)

Knee reaping is when a BJJ practitioner brings their leg across the mid line of their opponent while controlling the opponent’s foot between their hip and armpit which can create a twisting force on the knee.

It is very common in leg entanglements such as Ashi Garami (also known as Single Leg X).

The reason why knee reaping is so infamous is that IBJJF tournaments and some other organizations will immediately disqualify a competitor for such a seemingly harmless position.

It’s not necessarily the position that is dangerous, but the movement of the competitor that is being put into it that can cause injury. If they move in a uncontrolled or explosive manner serious injury can happen.

Key Takeways

  • Knee reaping is when a BJJ practitioner brings their leg across the mid line of their opponent while controlling the opponent’s foot between their hip and armpit which can create a twisting force on the knee.
  • The IBJJF (International Brazilian Jiu Jitsu Federation) is notorious for disqualifying competitors for knee reaping
  • As of January 2021, knee reaping and heel hooks are allowed for Brown and Black belts at the Adult No Gi Division only

 Here are the 5 conditions to remember that make a knee reap valid: 

  1. Thigh placed behind the opponent’s leg
  2. Calf on top of opponent’s body above the knee
  3. Foot beyond vertical mid line of the other person’s body
  4. Applying pressure from outside
  5. Keeping the leg of the foot at risk trapped 

Tips for Knee Reaping:


  • Do not straighten the reaped leg until you are clear of the reaping pressure.
  • Avoid moving your hips away from the attacker, which can inadvertently straighten the leg.
  • Do not spin against the direction of the applied force to prevent worsening the situation.
  • Try to control and remove their foot from the top of your hip before attempting to escape.

Attacker (Knee Reaper):

  • Keep your hips close to your opponent’s to maintain effective control during the reap.
  • Be prepared to ease pressure during training if your partner incorrectly straightens their leg to avoid causing injury.

Why Is Knee Reaping Used in BJJ?

Again, knee reaping is a term used to describe a specific leg entanglement that applies pressure on an opponent’s knee joint.


  • To control an opponent
  • Secure leg submissions
  • Transition into dominant positions (via sweep)


  • Knee reaping provides a high level of control over the opponent’s leg, which can lead to several submission opportunities or a sweep
  • It impedes the opponent’s mobility, making it difficult for them to escape or improve their position.


  1. Engaging the opponent’s leg by wrapping one’s own leg across the opponent’s thigh.
  2. Placing the foot behind the opponent’s knee or hip to create leverage.

Despite its tactical advantages, it is important to understand that knee reaping is often prohibited in competitions due to the elevated risk of injury it poses, particularly to the ligaments in the knee.

Usage in Practice:

  • In a controlled training environment, practitioners may explore knee reaping to learn to defend against it and understand its mechanics for educational purposes
  • Awareness and skillful application are critical since safety is a primary concern in BJJ practice.

Knee reaping is generally not a core technique in BJJ but rather a nuanced aspect specifically used in leg entanglements.

 Is Leg Reaping or Knee Reaping Legal in IBJJF?

If you are a white, blue or purple belt in BJJ, then yes knee reaping is considered illegal in IBJJF tournaments. 

However, if you are an advanced level (brown or black) as of January 2021, both knee reaping and heel hooks are legal for No Gi competitors only (it is still illegal for Gi competitors of all levels).

Here are some other illegal moves or technical fouls for IBJJF tournaments:

Image from IBJFF Rules and Regulation

Does ADCC Allow Knee Reaping?

For the ADCC World Championships and Qualifiers, knee reaping and heel hooks are allowed.

For ADCC Open Tournaments knee reaping and heel hooks are allowed for the “Professionals” category. However, the Advanced, Intermediate and Beginner categories do not allow heel hooks.

Should You Train Knee Reaping and Other Leg locks?

Training for leg attacks such as knee reaping and leg locks involves a sophisticated understanding of leverage and joint safety. They should be incorporated into a practitioner’s repertoire in a staged manner, respecting the progression of their skill level and the rules of the sport.

Main rule for all levels: always move in a controlled manner and train with a partner who you trust

Beginner Level

  • Focus: Emphasize defense and positional awareness.
  • Submissions: Limited to straight ankle locks.
  • Training knee reaping? Can be trained with a strong focus on control

Intermediate Level

  • Focus: Develop a deeper understanding of leg entanglements.
  • Submissions: Begin learning more diverse leg locks, maintaining a high emphasis on safety.
  • Training knee reaping? Can explore the position more and gain a deeper understanding of different outcomes from the position

Advanced Level

  • Focus: Refine leg attacks and understand nuanced positions.
  • Submissions: Expand to toe holds, heel hooks, and knee reaping with full application.
  • Training knee reaping? Advanced technical understanding and how to deal with specific counters, movements, and gain deeper awareness of submissions available as well as chaining submissions

In Competition

  • Rule Sets Vary: Familiarize oneself with specific rules regarding leg locks of the competition.
  • IBJJF: Recognizes heel hooks and knee reaping for adult black and brown belts in No-Gi Divisions.
  • Training knee reaping? Essential for competitors at legal belt levels (Adult Black and Brown No Gi Divisions), especially where it’s allowed to capitalize on the full range of techniques.

What is False Reap in BJJ

Knee Reap
False Reap

A standard knee reap typically involves control from a position such as single leg X (Ashi Garami), where the practitioner’s body and arm control the lower part of the opponent’s leg while their own leg applies inward pressure on the opponent’s knee.

In contrast, a false reap is similar in that the attacker’s top foot is on the defender’s hip however the defender’s leg is not trapped between the attacker’s arm and hip.

The concept of a false reap refers to a scenario where a position may appear as knee reaping but does not meet the criteria to be classified as such. To better understand this, it’s important to differentiate between actual knee reaping and positions that superficially resemble it but are permissible under standard BJJ rule sets.

Again, a knee reap typically occurs when a practitioner places their thigh behind an opponent’s leg and their calf across the body, above the knee, creating pressure from the outside. The foot must pass the vertical mid line of the opponent’s body. This action can impose dangerous torque on the knee joint and is often penalized due to the risk of injury.

Characteristics of a False Reap:

  • Thigh Positioning: The practitioner’s thigh is behind the opponent’s leg without applying pressure from the outside.
  • Calf Placement: Instead of crossing over above the knee, the calf may rest below the knee joint or alongside without exerting pressure.
  • Foot Position: The foot does not cross the vertical mid line of the opponent’s body.

A false reap, therefore, involves leg entanglement where the necessary elements to constitute a knee reap are not present. Practitioners should still exercise caution to ensure their moves don’t transition into an illegal reap and to maintain the safety of all participants.

Other Frequently Asked Questions

How can one identify a knee reap in Brazilian Jiu-Jitsu?

A knee reap occurs when a competitor places their thigh behind their opponent’s leg and the calf across the opponent’s body above the knee, while the foot passes the body’s mid line, applying lateral pressure to the opponent’s knee joint.

What are the potential injuries associated with knee reaping in BJJ?

Knee reaping can lead to serious knee injuries, such as ligament tears or strains, particularly to the medial collateral ligament (MCL) or anterior cruciate ligament (ACL), due to the unnatural twisting pressure it places on the joint.

What constitutes a false reap, and how is it different from knee reaping?

A false reap involves similar leg positioning to a knee reap but without the intent or action of applying pressure to the opponent’s knee, thus not putting it at the same risk of injury and not typically resulting in disqualification under IBJJF rules.

Can blue belts do knee bars?

In most competitions like IBJFF, UAEJJF and others actually deem the following illegal for white and blue belts: 

  • Heel hooks
  • Knee bars
  • Toe holds

Although, white and blue belts are allowed to perform ankle locks.

Are calf slicers legal in IBJJF?

Calf slicers are legal in IBJJF competition for the advanced ranks. Therefore, brown and black belts can use this attack in both Gi and No Gi IBJJF events.