Watch Jiri Prochazka swim 30 meters under a frozen lake

Jiri Prochazka continues to test his limits in unconventional ways.

A former UFC light heavyweight champion, Prochazka is known to be one of the more eccentric personalities in MMA. Back when he was champion, Prochazka spent three days without water in a dark room as a form of mental training, saying it allowed him to “work with his demons.” Before that, Prochazka would punch trees up to 500 times a day in preparation for his fights. Now, “BJP” has one-upped himself yet again.

On his YouTube channel on Wednesday, Prochazka released a mini-documentary about his journey to swim 30 meters under a frozen lake.

Ice diving is generally considered to be a dangerous endeavor, with an elevated threat of drowning along with hypothermia and other risk factors. But for someone always looking to test his limits, it presented Prochazka with exactly the sort of challenge he loves.

“Everything I do here, regarding the breath, regarding all these various trips to the mountains, climbing mountains, training martial arts, MMA, all these things simply help me, mainly and above all, to keep myself fully under control; to expand my self confidence, the spirit with which I go into battle,” Prochazka said. “A person doesn’t actually go into the MMA cage only with what they’ve trained, but they go there with their entire history, with everything, all the hard things they experience in life.”

Prochazka most recently fought in January, knocking out Jamahal Hill at UFC 311.