Curving Knee

Last updated: May 25, 2026

What is a curving knee?

The curving knee is one of the core knee strikes from Muay Thai, where it is known as Khao Khong (เข่าโค้ง). It carries several other names depending on the source: side knee, roundhouse knee, lateral knee, round knee strike, and curved knee. All refer to the same strike, a knee delivered along a curved or circular path rather than driven straight up.

The technique exists for a specific problem. When two fighters are pressed chest to chest in a tight clinch, there is no room to chamber and fire a straight knee upward. The curving knee solves that range issue by coming around the side of the opponent’s body, slipping past their guard and arms to land on the ribs, obliques, or floating ribs. Wikipedia’s entry on knee strikes makes the point that the curving variation thrives precisely where the straight knee fails: in spaces too tight to chamber a forward thrust, and against opponents who have already learned to shield against the more obvious option.

Power comes from hip rotation rather than forward drive. The striking leg sweeps inward in an arc, with the hips torquing in the same direction to generate force, similar to the mechanics of a roundhouse kick scaled down to knee range.

How the curving knee works

Where a straight knee thrusts forward like a spear, the curving knee travels sideways like a hook. The knee is brought up and around, with the hips rotating to whip the leg inward, and the contact point is usually the front or inner edge of the knee rather than the kneecap itself.

The technique is most often seen during the clinch, when a fighter is unable to create the upward space needed for a Khao Trong. Muay Thailand attributes the strike’s effectiveness to two things: the unfamiliar angle, which fighters trained to block forward knees don’t always see coming, and the rotational power that the hip turn loads into it. The targets are almost always to the side of the body: floating ribs, obliques, and sometimes the hip or outer thigh when the fighter is hooked around the back.

Curving knees are not knockout strikes in the way a flying knee or a clean straight knee to the chin can be. Evolve Vacation frames the technique as an attrition tool more than a finisher. The damage pales next to a clean straight or diagonal knee, but the curving variation grinds away at the ribs and obliques, sometimes the outer thigh, building wear that adds up across a fight. The value is accumulation. Repeated curving knees to the same patch of ribs wear an opponent down over rounds and score points in promotions that reward clinch work.

Curving knee vs. straight knee

Most people searching for the curving knee already know what a straight knee looks like and want to understand what makes the curving version different. The comparison below covers the main contrasts.

Feature	Curving knee (Khao Khong)	Straight knee (Khao Trong)
Motion	Lateral arc, rotated from the outside	Forward thrust, driven straight up
Range needed	Minimal; works in tight, chest-to-chest clinch	Needs space to chamber and fire
Power source	Hip torque and rotation	Hip thrust and forward drive
Typical target	Ribs, obliques, side of abdomen, hips	Solar plexus, sternum, abdomen, head
Knockout potential	Low to moderate; wears down rather than ends	High when it lands cleanly on the chin or solar plexus
Most common position	Locked clinch with no space between fighters	Open stance, plum clinch, or any range with room

The strikes complement each other. A fighter who only throws straight knees becomes predictable in the clinch, and an opponent who frames or sprawls forward kills the technique. Mixing in curving knees forces the opponent to defend both the line up the middle and the angles coming around the sides.

Where the curving knee shows up in MMA

In modern MMA, the curving knee appears most often during clinch exchanges against the cage. When fighters lock up in over-under or double-collar tie positions and pressure each other into the fence, the space between them collapses. That is when a curving knee can land where a straight knee cannot.

It is more common among fighters with Muay Thai or kickboxing backgrounds, since the technique is part of the standard knee curriculum in those arts. Wrestlers and BJJ-first fighters tend to use knees less frequently and lean on the straight or diagonal varieties when they do.

The curving knee is legal under the Unified Rules of MMA used by the UFC and most major promotions. Standard knee restrictions still apply: a fighter cannot knee the head of a grounded opponent. (For the full breakdown of what counts as a legal versus illegal knee, see Speak MMA’s guide on illegal knees in MMA.)

In commentary, the strike is rarely called a curving knee by its Thai name. American broadcasters more often describe it as a “side knee,” a “knee to the body,” or simply “knees in the clinch.”

Other names for the curving knee

Curved knee: interchangeable with curving knee

Khao Khong: the Thai term, used in Muay Thai instruction

Side knee: common English shorthand, used by commentators and coaches

Roundhouse knee: emphasises the rotational mechanics, similar to a roundhouse kick

Lateral knee: used in technical writing, including Black Belt Wiki

Round knee strike: common variant phrasing

Frequently Asked Questions

Is a curving knee the same as a horizontal knee?

No. The horizontal knee (Khao Tat) travels parallel to the ground and is typically thrown from outside the clinch as a counter or shield. The curving knee comes in a tighter arc and is thrown from inside the clinch when there is no space for a straight strike.

Where does the curving knee come from?

The technique originates in Muay Thai, where it is one of several named knee strikes. It has been part of the Thai clinch game for generations and entered MMA along with the broader adoption of Muay Thai techniques.

What part of the knee makes contact?

Usually, the inner or front edge of the knee, not the kneecap. Fighters often tuck the heel toward the buttock to sharpen the strike and land with bone rather than the soft area below the patella.

Why isn’t the curving knee as common as the straight knee in MMA?

MMA fighters break clinches faster than Muay Thai fighters because of the threat of takedowns and the cage. The curving knee shines in extended clinch exchanges, which are less common in MMA. Straight and diagonal knees fit the shorter clinch windows better.

Can a curving knee score a knockout?

It is uncommon but possible. A curving knee to the floating ribs can crack a rib or knock the wind out of an opponent and end the fight by TKO. Knockouts to the head from a curving knee are rare because the trajectory makes it hard to land cleanly on the chin.

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Sources

1. Wikipedia. “Knee (strike).” Accessed May 2026.
2. Muay Thai. “Muay Thai Knees: Explained.” Accessed May 2026.
3. Evolve Vacation. “The Different Types Of Knees In Muay Thai.” Accessed May 2026.
4. Black Belt Wiki. “Muay Thai – Curving Knee Strike.” Accessed May 2026.
5. Evolve University. “The Ultimate Guide To Muay Thai Knees.” Accessed May 2026.
6. Muay Thailand. “Muay Thai Knees.” Accessed May 2026.

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