I don't agree with the idea that athletes can't achieve without doping the same results. Firstly, we have to look at different doping for different events : for example, from 1988 practically throwers were not able to achieve similar performances, except for Ryan Crouser, who is a real freak of nature. In discus we are in the range 68-70m against 70-72 of the past, in hammer we have winners with 81m when in 1988 there were 4 athletes always over 84m, this for men : for women was still more different. The percentage of decrease after the "steroid age" for female throwers is around 10%. The same happened for jumpers : in high jump now the best are under 2.40, 30 years ago there were athletes like Sotomayor 2.45, Sjoeberg 2.43 and some other over 2.40. World records in jumping events, men and women, are very old.
So, we can say that without steroids at the moment is not possible to enhance the muscle strength till the same level possible with steroids.
Different is the case of blood doping. I have too many examples, among my athletes and other top athletes of the past and of the present, that, with REAL PROPER TRAINING, it's possible to better a WR training in clean way.
I agree that, when the aeroibic level is low (for example, after a bad injury or a long resting period), using EPO or other kind of blood manipulation, you can reach a level of 90% of your best Aerobic Power in very short time, for example in two months, when with training only you need to work for six months. But, after this, for moving from 90% to the top personal level, doping can't add anything to a real training.
The stay for long periods in altitude, for example, produces modifications in the personal physiology that can last for long time, but go back again if athletes stay sea level for 5-8 months after the period in altitude.
Nobody denies that, for example, with EPO it's possible to recover in shorter time, but the real question is : WHERE IS IT WRITTEN THAT HARD SPECIFIC TRAINING 3 TIMES PER WEEK CAN PRODUCE BETTER RESULTS THAN TOUGH TRAINING TWICE PER WEEK OR THAN ONE SESSION EVERY 5 DAYS DURING THE SPECIFIC PERIOD ?
The most important reason in training is to create the possibility to better support the SPECIFIC TRAINING. But, in any case, the QUALITY of specific training must be the same for analogous performances, but the full picture of a specific period, for athletes of different typologies (for example, fast or resistant typology of athletes for 1500m), is designed in very different way.
I give an example : if I want athletes running 3'30" in 1500m, a session such as 5 x 500m in 1'10" (race pace) with 4 min of recovery is the same for the fast and the resistant. However, for the fast (for example, able to run 1'44" in 800m) we see a higher accumulation of lactate, but also a different adaptation to remove in shorter time the producted lactate from his fibers. For this athlete, two easy days before the next training are enough. Instead, for the resistant type, the production of lactate is lower, but the time of permanence of it in the fibers is longer : this athlete needs one day more for fully recovering.
Opposite if we go for 10 km fast : for the resistant, one easu day id enough, while the fast feels tired for the next 3-4 days,
This means the secret is to evaluate the typology of the athlete before giving his training : what can't change, is the level of the workout, but the length of the recovery can be completely different, and at the end they are able to achieve the same performance.