Roger Federer has echoed calls by Andy Murray for more drug testing to be carried out in tennis.
The world number one believes that testing isn't as prevalent in tennis as it once was.
The 31-year-old told BBC Sport: "I feel I'm being less tested now than six, seven, eight years ago.
"I don't know the reasons we are being tested less and I agree with Andy, we don't do a lot of blood testing during the year. I'm OK having more of that."
Doping in sport has been a high-profile issue recently following revelations surrounding the career of cyclist Lance Armstrong.
