(Reuters) – A group of U.S. athletes
protested on Twitter on Sunday over curbs on appearing in
commercials during the Olympics in what looked like a concerted
challenge to rules designed to protect Games sponsors.

Athletes including Dawn Harper, gold medallist in the 100
metres hurdles in Beijing four years ago, took to the social
networking site to call for the restrictions to be relaxed.

"I am honored to be an Olympian but #wedemandchange #rule
40," Harper tweeted, accompanied by a picture of a group of U.S.
team mates in a meeting room. Others including triple Olympian
Sanya Ross-Richards echoed the message.

The target of their ire was rule 40 of the Olympic Charter
which forbids athletes from taking part in advertising for
anyone except sponsors during a Games.

The rules protect the 11 international companies including
Visa, McDonald's and Coca-Cola which help to bankroll the
Olympic movement, paying around $100 million each for four years
of global rights to sponsor a winter and summer Games.

Those companies and sponsors of national Olympic committees
are exempt from rules designed to prevent what is called "ambush
marketing", non-sponsors getting free publicity on the back of
the Games.

However, the curbs mean that athletes are cut off from some
of their own individual sponsors just when they are enjoying
maximum exposure.

Guidance issued to athletes and their agents before the
Games warned them that they risk sanctions including
disqualification if they broke the rules.

The International Olympic Committee (IOC) has been actively
encouraging athletes to use social media during the Games which
opened on Friday.

However, the guidelines on blogging contain a warning about
adhering to the rules on advertising.

(Editing by Tony Jimenez;