No, it's not what you think.
It was actually part of a celebrity 17-man arm wrestling tournament that also included UFC fighters Alistair Overeem, Norifumi "Kid" Yamamoto and Mark Hunt, as well as other MMA stars well known in Japan like Kazushi Sakuraba and Kevin Randleman, and famous kickboxers Jerome LeBanner and Francisco Filho.
Sapp won the tournament, beating Baruto, a 415-pound Estonian who was a famous sumo in Japan until retiring earlier this year. Sapp beat a sumo named Aoiyama and Terry Holland, whose background is not known, before beating Emelianenko in the semifinals.
Sapp is easily most famous MMA fighter in Japan, even though he's turned into a joke in recent years. He was a hard to explain cultural phenomenon a decade ago and was a huge ratings draw for years when he would fight on television.
In his first-round match, Emelianenko put the arm down of Filho.
He next beat Hakuho, a Mongolian sumo Grand champion. That is the equivalent of being a Hall of Famer in that sport as there have been less than 100 Grand Champions in history. He followed beating Nigerian comedian Bobby Ologun, who did a number of high-profile MMA fights on Japan's biggest shows, before Emelianenko lost to Sapp.
The tournament was a live network special that aired in prime time on the Fuji Network in Japan. A similar tournament last year, also won by Sapp, who beat Overeem in the finals, was a big ratings hit.
Overeem was eliminated in the first round by an Egyptian sumo named Oosunarashi. Hunt, who lost to Sapp in the quarterfinals last year, was eliminated in the first round by LeBanner. LeBanner, one of the most popular kickboxers in Japan from the heyday of the sport their in the late 90s and early 00s, then beat handball superstar Daisuke Miyazaki, before losing to Baruto in the semifinals.
Yamamoto, who is still under UFC contract but hasn't fought in almost two years due to injuries, lost in the first round to Koki Kameda, a former WBC flyweight boxing champion. Kameda is Japan's most popular boxer.
Sakuraba was put down in the first round by the much bigger Kazuhiro Kiyohara, a 46-year-old retired baseball superstar who is a legend in Japan as his 525 career home runs are fifth best of all-time.
The other former MMA fighter in the tournament was Yoshihiro Takayama, best known as a pro wrestler in Japan, but his Pride match with Don Frye is among the most famous MMA fights ever held in Japan. Takayama was eliminated by Ologun.
Randleman was eliminated in the first round by Baruto.