Kayla Harrison is at the center of a dispute with Ronda Rousey, who returns to MMA on May 16.
What happened?
Rousey and Harrison have a long history, dating back to their judo training days under Jimmy Pedro.
Harrison moved to Massachusetts as a teenager to train with Pedro, who also coached Rousey.
The two women first competed against each other at the 2005 U.S. Judo Championship.
Why it matters for Kayla Harrison
Rousey has positioned herself as a formative influence on Harrison's career path into MMA.
But Harrison has called Rousey's story about her judo training days a "blatant f**king lie".
Rousey responded by labeling Harrison a "brat little sister".
What comes next?
Harrison has publicly invited Rousey to meet her in the Octagon after Rousey's Netflix card fight against Gina Carano.
The fight is scheduled to take place on May 16 at the Intuit Dome in Los Angeles.
Harrison has made no effort to soften her observation about the gap in competitive experience between Carano's last fight in August 2009 and the current MMA scene.
Rousey's return to MMA has brought the dispute back into the spotlight.
Harrison's invitation to Rousey has left the door open for a potential fight between the two women.
The UFC women's bantamweight champion has been vocal about her thoughts on Rousey's credibility.
As Rousey prepares to face Carano, Harrison's comments have added an extra layer of tension to the upcoming fight.
The dispute between Rousey and Harrison is likely to continue in the lead-up to Rousey's Netflix card fight.