A leglock is a joint lock that is directed at joints of the leg such as the ankle, knee or hip joint. A leglock which is directed at joints in the foot is sometimes referred to as a foot lock and a lock at the hip as a hip lock. Leglocks are featured, with various levels of restrictions, in combat sports and martial arts such as Sambo, Brazilian Jiu-Jitsu, catch wrestling, mixed martial arts, Shootwrestling and submission wrestling, but are banned in some sports featuring joint locks such as judo.

As with other jointlocks, leglocks are more effective with full body leverage. Some attack the large joints of the knee or hip and involve utilizing leverage to counteract the larger muscle groups, while others directly attack ligaments in the knee or the smaller joint of the ankle. Leglocks can involve control positions such as the inside leg triangle or leg knot to maintain control while applying the attack or transitioning between two attacks, though they and some other control positions are banned in Brazilian Jiu-jitsu competition. Some other leglock control positions have been adopted into modern BJJ and submission grappling competitions as "guards" such as the snake guard, one-legged X-guard, and 50/50 Guard, where they are used for both leglocks and to reverse into dominant positions from the bottom.

Dean Richard Lister (February 13, 1976) is an American mixed martial artist and a former King of the Cage champion. He currently fights at the Middleweight division after moving down from the Light Heavyweight class. Lister's sparring partner and the former UFC light heavyweight champion Tito Ortiz invited Lister to be his assistant grappling coach on the third season of the Spike TV reality show, The Ultimate Fighter.

Lister grew up in a military family and lived in several South American countries, including Venezuela and Panama. Lister speaks several languages. He lived in Panama during the U.S. invasion in 1989, and, according to Lister, he was "right in the middle of a serious combat zone". After living in several different cities in the United States, Lister's family settled in San Diego for Lister's high school years.

Lister often fought as a kid, mostly due to a combination of being the "new kid", a foreigner, and being small for his age. The need to protect himself led Lister to wrestling and martial arts.

Rigan Machado is an 8th degree red and black belt in Brazilian Jiu-Jitsu earning his rank under Carlos Gracie Jr. He is a former Jiu-Jitsu world champion and a veteran of the ADCC. Machado holds a victory over Ron Tripp, the only person credited with a victory over Rickson Gracie. Machado currently teaches out of his California Academy.

He began training at the age of 5 with his cousins, "The Gracie Family". In an interview when asked about his exact relationship with the Gracies Rigan said "My mother's sister married the founder of Brazilian Jiu-Jitsu, Carlos Gracie." Like all children took it more as a game than really as something he wanted to do for the rest of his life. He started to take training and competing more seriously at the age of 14. This is the time where Rigan would start to train everyday on the mat. From the age of 14 through 21, he won the Brazilian National Championships every year and every belt division. He amassed a record of 365 wins and 2 losses in Brazilian Jiu-Jitsu competition. He also created a record by having 19 matches in one day and finishing all of them by submission. He remains unbeaten in Brazilian Jiu-Jitsu in more than 13 years of competition. His training sessions were all very technical and intensive under the eye of his two instructors Rolls Gracie and Carlos Gracie Jr. He also trained with his other cousins such Rickson Gracie, Rorian Gracie, Rillion Gracie, his uncle Carlson Gracie Sr, and his brothers.

Braulio Estima is a 2nd degree black belt in Brazilian Jiu-Jitsu. He received his black belt from Carlos Gracie Jr on January 4th, 2004. Throughout his grappling career, he has won in many Brazilian Jiu-Jitsu tournaments across the world, such as the Mundials, ADCC, Pan American Championship, and European Championship. His long list of accomplishments has made him well respected among other Brazilian Jiu-Jitsu practitioners, such that some consider him one of the top Brazilian Jiu-Jitsu practitioners in the world. Eddie Bravo, a black belt Brazilian Jiu-Jitsu practitioner, has said that Estima is among the top 3 Brazilian Jiu-Jitsu grapplers in the world.

Braulio Estima was born on June 10th, 1980 in Recife, Brazil. He was first exposed to martial arts at the young age of 9, where he was introduced to Judo. However, a year later, his judo instructor suffered an untimely death, which caused Estima to take a break from martial arts. Six years later, he decided to come back and began training Judo and Brazilian Jiu-Jitsu at the Gracie Barra Jiu-Jitsu Academy.

Francisco Santos Miranda, III (born May 24, 1979), better known as Frank Mir, is an American mixed martial artist, as well as a black belt in Brazilian Jiu-Jitsu and Kenpō Karate.

Mir, one of the most accomplished heavyweights in MMA history, is a two time UFC Heavyweight Champion . He currently holds the record for most victories in the heavyweight division of the UFC with 14 and most wins by submission in UFC Heavyweight division history with 8. He is also the only man in UFC history to win a bout by toe hold. As of January 2012 he is ranked the #4 In the ESPN MMA Power Rankings.He holds the distinction of being the first and only man to both knock out and submit MMA legend Antônio Rodrigo Nogueira. Mir is the only person to submit former UFC Heavyweight Champion and NCAA Division I wrestler Brock Lesnar and highly regarded striker Cheick Kongo. Frank Mir has had more fights in the UFC than anyone else currently competing in the heavyweight division.

His father convinced him to begin wrestling, on the basis that it could help him avoid submissions. Mir then began wrestling at Bonanza High School in Las Vegas, Nevada where during his junior year he lost his first nine matches. During his senior year (1998) he went 44–1 and won the state championship. He was also on the school's football team that reached the Southern Zone semifinals in 1997 and where he played as fullback and defensive end. He also took up track and field in 1998 where his discus throw of 177 feet, 10 inches is still a Sunset Regional record.