Sports injuries are common. It's what happens after the game that might come as a surprise.

Residents of a city in Wales take a post-game beating, especially when the locals wins.

Soccer and rugby are popular in Cardiff, the largest city in Wales. Matches often attract more than 70,000 fans.

Assaults in the city average 21 in a typical two-day period when there are no games, based on cases at the city's only emergency center from 1995 into 2002. On game days, when the home team lost, the total for that day and the next was 25, on average. When Wales wins, assault injuries rose to an average of 33.

Whether the games were home or away mattered little, according to the study, which was announced Wednesday and is detailed in the journal Injury Prevention.

"These analyses suggest that assault may not be the result of negative factors associated with a national team losing, but the result of a positive event (winning)," the researchers write.

Perhaps victory increases self-confidence, assertiveness, patriotism and drinking, all of which can lead to violence, the researchers say. They point out that other studies have shown domestic violence by men goes up when their team wins.

The research was led by Vaseekaran Sjvarajasingam at Cardiff University.