Eli5: From the early 20th century until now the 100m sprint world record has improved for over a second. Is it only better training, or have the doping methods developed to the point of being undetectable?

Question

Eli5: From the early 20th century until now the 100m sprint world record has improved for over a second. Is it only better training, or have the doping methods developed to the point of being undetectable?

In: Biology

Answer 1

It’s mostly technology. Shoes, track surfaces, nutrition, training methods, medicine, aerodynamics and lightweight clothing.
Some other reasons that have multiple levels:
Travel: it used to be that only certain people could even make it to a race, now almost all high level athletes can fly around the world.
Number of lanes on a track: there used to only be 5 or 6 lanes, meaning more qualifying heats were run and athletes had to pace themselves or were more tired by the finals.
Reduction in poverty: if your family has no money, or even no food, it’s unlikely you rise to the level of an elite sprinter even if you were genetically destined for it.