The interview repeatedly asked about increasing BLOOD TESTING. That would literally be a real pain. As anyone can tell you who has had frequent blood tests, the needle can result in bruising and muscle soreness. Injection points are also in danger of infection. I think its unfair to ask athletes to endure this kind of invasive testing.
Urine or perhaps saliva testing is the only other way. However part of the problem is that the technology for testing is always behind the latest performance enhancing drug.
Steroids don't do that much for tennis players who rely more on reflexes, balance, quickness and skill rather than strength. It is the oxygen enhancing PEDs which Dr. Fuentes is said to have used on some Spanish players which are the most concerning. This type of PED allows body to make greater use of oxygen in the blood. This increases endurance for long grinding 5 setters. You still have to be a great tennis player to win, but the enhanced oxygen PED gives a player vastly increased endurance.
Thanks for the insight