[chrisandchris]

Wasn't there a study whose result was that people are not actually running faster but the better results are mostly attributed to changing/improving grounds and better shoes?

Edit: Can't find the study anymore. This one [1] at least partially attributes to material.

[1] https://www.balticsportscience.com/journal/vol17/iss2/2/

[tstrimple]

Training has also evolved drastically over time at the highest end of athletics. Periodization, nutrition, recovery and the size of the talent pool being scouted are all occurring alongside the advances in materials and equipment. It would be difficult to separate them effectively.