A compression lock, muscle lock, muscle slicer or muscle crusher, is a grappling hold which causes severe pain by pressing a muscle into a bone. A compression lock can cause a joint lock in a nearby joint when it is applied by squeezing a limb over a fulcrum. A forceful compression lock may damage muscles and tendons, and if accompanied by a joint lock, may also result in torn ligaments, dislocation or bone fractures. Compression locks can be used as pain compliance holds, and are sometimes featured in combat sports as submission holds.
Luta Livre black belt Nicolas Renier is arguably the most accomplished No Gi Grappler in Europe, having been Fila World Grappling champion, and being the only European to participate in 6 ADCCs. He teaches in Paris, in his club called NRFight Club.
Here he shows 3 truly nasty compression locks that are common in Luta Livre and that can be applied in BJJ:
