Armlocks have always played a major role in the ne-waza (ground game) of Japenese Judo & Jujitsu,Brazilian Jiujitsu, Russian Sambo, and now submission fighting and submission wrestling because of their immediate effectiveness.
Armlocks fall under the category of kansetsu-waza or joint locks. Judo teaches armlocks as the third section of the ground work kata in 5 different variations. This tape series stresses mainly the straight and reverse armlocks also known in Japanese as the juji-gatame and gaku-juji-gatame.
In order to become proficient in the use of the Juji in competition, one must 'ingrain' it into their muscle memory through high repetition with the use of a cooperative partner or on a submission dummy.
Erik Paulson Wikipedia
Erik Paulson (born 1966) is an American Mixed Martial Artist raised in Minnesota and currently residing in California. He is the first American to win the World Light-Heavy Weight Shooto Title in Japan - a title he defended for 5 years.