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The claim that humanity with all the money, medicine, science, and effort placed into recruiting and training world class sprinters has only managed to achieve less than 70% of the potential top speed for a human and that someone could pop up in the next couple decades that could drop the world record by more than it has moved in the last century in one fell swoop is not plausible. Sprinting is too close to raw power output for this kind record movement and if your analysis says that it is then you need to go back to the drawing board.