TOKYO (Reuters) -- Sumo wrestlers who fancy themselves as nightclubbers or footballers face a backlash from traditionalists in the roly-poly sport.

Eager to clean up sumo's tarnished image, officials are mulling the idea of producing a handbook for the bare-buttocked giants to bone up on the etiquette of the ancient Japanese sport.
Japan's government recently ordered sumo officials to clean up their act after the arrest of a former gym chief on suspicion of assault following the death of a 17-year-old wrestler.
The affair came after Mongolian “yokozuna” Asashoryu was banned after being caught on TV playing soccer while supposedly injured, triggering outrage among the sumo establishment.
Concerned about a lack of discipline in a sport no longer dominated by Japanese wrestlers, sumo officials could approve a manual to help keep its protagonists in line.
According to Japan's popular Nikkan Sports newspaper, top tips for proper sumo protocol include not being seen strolling around Tokyo night spot Roppongi in a T-shirt.
Also to be avoided away from the ring are shorts and sweatshirts, while the clenching of fists after winning a bout would also send wrestlers to the back of the class.
The sumo handbook would be illustrated with photographs, accompanied by a tick or a cross for the benefit of the dozens of foreign grapplers plying their trade in Japan.
“When I came into sumo we didn't have sweatshirts,” said Japan Sumo Association (JSA) official Isenoumi in support of the proposed guide, which could be formally approved next month.
“Clothes are different now so it is hard for young wrestlers to judge.”
Sumo dates back some 2,000 years and still retains many Shinto religious overtones.
Hawaiian Akebono became the first overseas wrestler to be promoted to the sport's elite rank of yokozuna in 1993, followed by Samoan-born Musashimaru in 1999.
Modern professional sumo has more than 60 foreign-born wrestlers in Japan, drawn from countries ranging from South Korea to Brazil with many more from Eastern Europe.