It's estimated that up to a third of the athletes that we'll watch at the Olympics, will be dopers. So how do you dope and get away with it?
Four researchers came together to discuss what it takes for top athletes to run a marathon in under 2 hours.
Sochi's elevation makes speed-skating world records unlikely.
Less than eight percent of Bolt's energy contributed to his motion during the 100 meters at the 2009 World Championships.
David Rudisha's world record 800-meter performance, and a look ahead to the women's final.