Catching the opponent's leg kick and sweeping their supporting leg.
Low kicks are utilized to damage the opponents legs, which causes the loss of dexterity, stability, and mobility. Being struck repeatedly by low kicks can often result in damage to bones, joints, ligaments and muscle tissue.[1] The sciatic nerve, which is the longest and widest nerve in the human body, beginning in the lower back and running through the buttocks all the way to the lower limb, is a frequent target for low kicks.[2]
A low kick being checked.
Checking
The most common defense against a low kick is known as "checking", where the leg is bent and brought up to protect the thigh. This causes the kicker to slam his/her shin into the defending fighters' shin or knee, causing pain and damage to the offender. In some instances, a well executed check of a low kick can break the leg of the offender — as it was the case when Chris Weidman checked Anderson Silva’s inside low kick in UFC 168, and most recently, when Uriah Hall checked Chris Weidman's inside low kick with the same result at UFC 261[3][4][5][6][7]
Notable examples of fighters using low kicks which affected the outcome of a match:
Maurice Smith stopped Travis Everett to retain the WKA World Heavyweight Championship in Mexico City, Mexico in 1983.
Maurice Smith stopped Raymond Horsey to retain the WKA World Heavyweight Championship in Atlanta, Georgia, USA in 1986.
Maurice Smith stopped Bill Morrison to retain the WKA World Heavyweight Championship in Las Vegas, Nevada, USA in 1987.
Changpuek Kiatsongrit stopped Rick Roufus in Las Vegas, Nevada, USA on November 5, 1988.
Maurice Smith stopped Steven Kruwell at the World Martial Arts Challenge (Las Vegas, Nevada, USA) on March 16, 1992.
Stan Longinidis broke Dennis Alexio's leg to win the ISKA World Heavyweight Oriental Championship at Clash of the Titans (Melbourne, Australia) on December 6, 1992.[8]
Thiago Alves utilized low kicks heavily against Josh Koscheck to win by unanimous decision at UFC 90 (Rosemont, Illinois, USA) on October 25, 2008.[13]