Axe-kicks are not illegal in the UFC. In fact, former UFC light heavyweight champion Jon Jones has used it on a few occasions during his career. However, axe-kicks to the head of a downed opponent, much like any other kicks in this regard, are considered illegal.
Watch Jon Jones's axe-kick attempt against Daniel Cormier, below:
Earlier this week, former UFC double champion Conor McGregor explained how he uses axe-kicks to deal with opponents pulling back from his high kicks. McGregor's tweet read:
Get the latest updates on One Championship Rankings at Sportskeeda and more
"I’m not disrespecting. I’m telling you, I’ve faced this defense habit a lot in my time where I knew every high kick I threw was being pulled back from and hitting air. I then began changing to an axe kick and came down on top with great success. That or the running roundhouse."
Although legal, axe-kicks are barely used in mixed martial arts, perhaps due to the takedown threat. This kick is a common sight in taekwondo and even Muay Thai fights.
A few of the illegal moves in the UFC
While an untrained eye might see MMA as a no-holds-barred sport, even the biggest mixed martial arts promotions in the world like the UFC have banned certain moves to ensure the safety of its fighters.
Headbutting
Very few sports like Maynmar's Lethwei accept headbutts during fights. The UFC has a strict no-headbutting policy. An intentional headbutt is a sure-fire way for a fighter to get point deductions from the referee.
A 2021 fight between Kevin Holland and Kyle Daukaus was ruled a no-contest after an accidental clash of heads knocked out Holland.
Watch Kevin Holland getting knocked out with an accidental headbutt:
Rabbit Punches
Punches to the back of the head are considered illegal. Rabbit punches are illegal in most mixed martial arts promotions.
Recently, former UFC champion Eddie Alvarez's ONE Championship fight with Iuri Lapicus was declared a no-contest due to an accidental rabbit punch by Alvarez.
Watch Eddie Alvarez's disqualification due to a rabbit punch below:
Eye Pokes
Eye pokes are illegal in the Dana White-run promotion. Accidental eye pokes will most of the time warrant a warning from the referee. Repeated eye pokes will result in point deductions.
If a fighter is unable to recover from an eye-poke, the fight is usually ruled a no contest.
Groin Strikes
The groin is one of the most sensitive areas of the body. As such, any strikes to an opponent's groin area is illegal in the Ultimate Fighting Championship. If a fighter is unable to recover from a groin strike, the fight will be declared a no contest.
Knees/kicks/stomps to the head of a downed opponent
Any kicks, stomps or knees to the head of a down opponent are illegal. Petr Yan originally lost his bantamweight title to Aljamain Sterling owing to an illegal knee by Yan to a downed Sterling.
Watch Petr Yan getting disqualified for kneeing a downed Sterling below: