How did humans evolve this much?

Looking at all the records and all the athletes scientists say that people went beyond the limit of what is humanly possible.


And as i see many bodybuilders, athletes they are FAR beyond what i thought is possible.


Example :


100 meter World Record Holder Asafa Powell





100 meters in 9.74 sec = about 23 mph





How did humans evolve so fast?


Is it steroids, chemistry ?


Is it effect of the environment?|||The record for 100 meters is 9.69 by Usian Bolt.


It is not a fast evolution when we are looking at recorded performances, but is a fast evolution when looking at the history of the world.


Improved training methods, brought about by increased knowledge of human performance and functions, along with better equipment, and track surfaces, and professionals who train all year are responsible for the improvement within the last 30 years in human performance.