A European Union panel will this week release its legal opinion on anti-doping rules that require Olympic-level athletes to disclose their locations every day, reports Reuters. A legal challenge has been lodged in Belgium on behalf of 65 athletes, including cyclists and volleyball players, who argue the rule breaks EU privacy laws. FIFPro, the soccer players’ union, is also mounting a case.

The panel’s decision will form the basis of a broader and far-reaching binding legal opinion by the European Commission, the executive arm which oversees EU legislation within the 27-nation bloc due to be published before the northern summer.