> I'd rather believe they're doping.

Funnily enough, you're correct in your belief, even if by accident and in defiance of your own preconception. Mechanical doping is the topic your speaking about! :)

Here's some of the more obvious examples out there:

https://www.youtube.com/watch?v=iSfLbALqUgM

https://www.youtube.com/watch?v=tZerARsCqAE

https://youtu.be/1CnyvcAFTlA?t=36

https://www.youtube.com/watch?v=Fbg4BjZna4Y

This video covers a bit of the history of mechanical doping. https://youtu.be/JMZbU6on43k?t=610