Russia's entire track-and-field team has been banned from the Rio Olympics. Do other athletes dope, too? Here's everything you need to know: Why were the Russians banned?Investigators found that Russia had for many years been running a massive, state-sponsored doping program for its athletes. The allegations first came to light in a 2014 German TV documentary, in which whistleblowers claimed "99 percent" of Russian athletes used banned substances, and that Russian officials both supplied the drugs and colluded with doping-control officials to cover up failed tests.