One of the main benefits of EPO is it allows the body to recover more quickly. The quicker you recover, the more often you're able to train with higher intensity and the faster you become. Instead of 2 high-intensity sessions per week, now you can do 4. And you're training runs are now at a higher level as well.
EPO doesn't just make you faster - it allows you to recover more quickly to train more often to become faster.
What is this BS!?!?? EPO does NOT help top tier athletes!!! Or is it just Kenyans that it doesn't help. I forget....