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.
Science
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That's actually what is happening here. Rather than a 'gut feeling' about human performance, someone/several people decided to try to model it with the best available information. If it's wrong, the next step is to prove why it's wrong and get a new 'best approximation'.
The next step is not to throw it all out because it doesn't sound plausible.
The fastest top speed ever achieved by a human was Bolt’s 12.42 meters/second (27.8 mph).
However, anatomical studies suggest peak speeds up to 15.6-17.9 m/s (35-40 mph) are achievable.
science btw
That's insanely fast. 30mph on a bike (flat, no wind) is real work. And that's with proper gearing and, you know...wheels.