Mark Henry's a wrestling AND power lifting legend ... but he ain't even the best athlete in his own house anymore -- 'cause his 2 young kids are dominating youth sports.
TMZ Sports talked to Mark about his 12-year-old son, Jacob, and 8-year-old daughter, Joanna ... who both qualified for the Junior Olympics.
FYI -- Mark's a 2-time Olympian who also placed 1st at the Pan-Am Games and Arnold Strongman Classic back in the day -- and just about every other power lifting event that existed.
It's his kids who are killin' it now.