Justin Gaethje’s Coach Says Even Pad Kicks Leave His “Nuts” Swollen

Justin Gaethje’s latest title win has led to another story about the force behind his kicks, this time from longtime coach Trevor Wittman, who says the UFC once tested fighters to find out who had the hardest bones in the promotion and Gaethje finished first.

Trevor Wittman says UFC test found Justin Gaethje had the hardest bones

In a recent appearance on the “JRE MMA Show,” Wittman said the promotion “did a test on him to see who has the hardest bones in the UFC” and that Gaethje had “the hardest bones,” adding another layer to the lightweight champion’s long-standing reputation as one of the sport’s most punishing kickers.

The remark appeared just days after Gaethje‘s title-winning performance against Ilia Topuria which came by TKO over Topuria in June 2026, giving fresh attention to any detail connected to the champion’s power.

Wittman framed the story with the kind of gym anecdote that tends to travel fast in MMA. Speaking about the US-born fighters’ kicks, he said even holding pads for them comes at a cost, explaining that a shot from the lightweight champ can leave the inside of his leg swollen despite the added protection. Gaethje then added the line that pushed the exchange into viral territory, joking that Wittman no longer lets him kick him because “He has a pad on, I kick him, and his nuts swell up.”

Gaethje had already referenced unusually dense bones in an earlier Joe Rogan appearance after his 2020 win over Tony Ferguson, saying the UFC Performance Institute had put him through a DEXA scan and that officials “can’t confirm or deny” he had the densest bones in the UFC. Wittman’s latest retelling gave that older claim a new burst of life.

A study published in the Journal of Exercise and Nutrition found that MMA fighters as a group showed very high bone mineral density compared with several other athletic populations, which helps explain why the idea of a fighter standing out in that category is not far-fetched.