How does one answer a question like that meaningfully? What counts as human? Suppose that all the humans in every generation who could beat 10 secs/100M were to cooperatively mate at each generation and select the top million offspring for the next generation of the experiment for 100 generations.  That would be a very modest experiment, evolutionarily speaking; 2000 years or less. I leave it to you to imagine the result after 100000 generations. I do not even dream of asking you to imagine the outcome of 1000 years of genetic engineering.

Now, would you call the offspring that resulted human? If not, why not? Because they could sprint faster than their grandparents? Our sprinters already do that. Because they don't look human? Who are we to call people with small feet (or hooves), large, forward-directed nostrils, flat ears, smooth heads, and massive thighs inhuman?

Well, I would guess something like 6 to 8 seconds.

And you?

What do You mean by "theoretical?

In practice, there are thousands of young men who

tried to run faster than 10 m/s since 1960, all in vain,

in spite of training this useless art for years.

Georg

 The current world record is 9.58 s, set by Usain Bolt. I recall reading somewhere that this would be close to a theoretical limit of human physiology, or some such. But obviously this is anecdotal.

 Each to his own, Georg. But all art and sport are, in a manner of speaking, useless. Speaking as an artist and a sport fan, I'd say that uselessness is pretty much a defining criterion. But it makes for great displays of excellence for the purpose of itself, which is enjoyable to do and to witness; and of the fitness of the performer, which seems to serve a biological purpose.

Hello Kinh,

with respect to my attitude to sports, You must know my preference

of irony.

Re the times of 100 m sprint; I think that the athletes of 1960 would

run in 9,6 seconds with today equipment and training and time measuring

methods. So this 10.0 (or 9.6)  seconds are just a limit by 50 years

experience.

Georg