Sir Bradley Wiggins is among athletes whose confidential medical records have been released by Hackers, who are suspected from Russia after stealing more medical files from the World Anti-Doping Agency (Wada) the bbc reports.
The athletes include Rio Olympic gold medalist and British cyclists Sir Bradley Wiggins, and Chris Froome, the three-time Tour de France champion.
There is no suggestion the athletes are involved in any wrongdoing.
Wada says the cyber attack is an attempt to undermine the global anti-doping system.
The records released by the group calling itself “Fancy Bears” mostly detail “Therapeutic Use Exemptions” allowing banned substances to be taken for athletes’ verified medical needs.
“Wada is very mindful that this criminal attack, which to date has recklessly exposed personal data of 29 athletes, will be very distressing for the athletes that have been targeted; and, cause apprehension for all athletes that were involved in the Rio 2016 Olympic Games,” said Wada Director General Olivier Niggli.
Mr Niggli said there was “no doubt” that the hack was retaliation against Wada for its report into Russian state-sponsored cheating and appealed to the Russian government to help stop it. The Russian authorities have denied any involvement.
The documents relate to 10 American, five British and five German athletes as well as one athlete each from Denmark, Russia, Poland, the Czech Republic and Romania.
It follows an earlier leak of documents relating to US athletes including multiple gold-winning US gymnast Simone Biles.