Ronda Rousey did her best to hide her disappointment as she touched down in the United States last week following her humiliating defeat, but she'd have been as well to do the same for her feet.

After she was knocked out following a kick to the jaw from Holly Holm in UFC 193, while she was on the canvas you could see the soles of her feet were clearly yellow and purple.

In a blown up photo from Ronda’s fight making the rounds on November 23, it focuses what looks like to be heavily bruised purple soles while her toes are a jaundiced yellow color. The question is how did they get to be this color?

During the fight in Melbourne two Sundays ago, there were controversial and unfounded suggestions it was a result of steroid use.

There have been cases of athletes developing jaundice — which causes a yellow pigmentation in the skin — after using steroids for more than two years.

Retired MMA star and one of Holly’s pals Julie Kedzie says it’s not from steroid use as some Reddit users speculated, rather it’s just a cold arena mat.

The material used on the floor of the Octagon rubbing off on the competitor's feet caused the coloring she said, while training and fighting in the cold could be another reason.

Other possible causes given for the discolouration of Rousey's feet ranged from circulation issues to plain old dirty floors.

Las Vegas-based fighting photographer Ryan Loco tweeted, “see that a lot on the fighter’s feet. Always freaks me out. I blame the canvas.” Julie chimed in to his comment with the reply “canvas and cold. My feet always turned yellow.”

She also shared a photo on her Twitter account giving a hard kick to a competitor’s head, and in it her feet appear to be somewhat yellow as well. In her discussion with Ryan she added “dis ma foot. Yellow too and I swear I didn’t juice EVER. I don’t think Rousey did/does either.”