UFC legend Ronda Rousey said she had to retire from the promotion in 2016 because of her history with concussions from her judo career.

Rousey is one of the biggest box-office draws in UFC history and was the first female fighter to sign with the promotion.

Her MMA amateur and professional career started with 15 straight wins, including her first 10 fights ending with her opponent tapping out to an armbar in the first round.

Rousey’s last three title defenses of the UFC Women’s Bantamweight Championship lasted a combined 64 seconds.

Yet, Rousey’s last two UFC fights ended with her being knocked out by Holly Holm and Amanda Nunes, both with vicious strikes to her head.

Rousey’s first UFC loss came in November 2015 after a brutal head kick from Holly Holm

Rousey has dedicated herself to her family and has mostly stepped away from combat sports

‘I’d like people to understand my reasons and motivations behind things,’ Rousey said on Instagram Live. ‘I was forced to leave fighting when I was faster, stronger, more skilled and had a better understanding of the art than ever before. It was a really hard decision to understand, one that my body made for me.’

‘I think there was just so much to (the loss against Holm) that I couldn’t talk about it in the form of an interview or article or anything like that, or there would be several filters between my words and people reading it,’ Rousey continued.

‘So much had to do with having so many concussions when I was in judo before I even got into MMA,’ Rousey added. ‘I couldn’t talk about it at all when I was doing MMA because it would literally put a target on my head and I might not have been allowed to compete any farther.’

After Rousey retired from the UFC, she signed with the WWE and was cleared for the company’s in-ring action.

Rousey’s last fight in the UFC lasted less than one minute in a TKO loss to Amanda Nunes

Rousey took bumps on the canvas despite professional wrestling veering into sports entertainment.

While with WWE, she competed in the first women’s match to headline WrestleMania, in a three-way bout also featuring Charlotte Flair, daughter of legendary professional wrestler Ric Flair, and Becky Lynch.

Lynch won the triple-threat contest in one of Rousey’s only pinfall loses in her time with WWE.

Rousey’s last match with WWE took place last summer against fellow former MMA competitor Shayna Bazsler.