A group of Belgian athletes are mounting a legal challenge against the whereabouts rule for out-of-competition drug testing, a move that could undermine the work of the World Anti-Doping Agency.
The athletes claim the rule, which requires them to notify testers of their whereabouts up to three months in advance so they can be located for doping controls, is an invasion of privacy.
If the case is successful in Belgium, it could be used as a precedent to challenge the ruling in other courts around the world.
A group of 65 football and volleyball players and cyclists have filed the case with Belgium's Council of State high court, which could take up to six months to issue a ruling.
Out-of-competition doping tests have become essential to catch cheats since many illegal substances can become untraceable by the time the competition starts. To perform such tests, WADA needs to know at all times where and when athletes can be traced.
Under the latest WADA code, athletes must specify one hour each day when and where they can be located for testing.
Under the rules, three missed tests or three warnings for failing to file whereabouts information within an 18-month period constitute a doping violation and can lead to athletes being banned.
The Belgian challenge uses privacy provisions within the Belgian constitution and the European Convention on Human Rights and Fundamental Freedoms of the Council of Europe to challenge the system.
Although the athletes stress they do not object to out-of-competition doping, they claim the current system is far too invasive, forcing them even to pinpoint when they go to the movies.