Why is it hard to go fast on water?
Why is it hard to go fast on water? Since the water moves back as you push it, you need to go twice as fast as that or you would stand still. So that's a running speed of almost 80 km/hr, which would be quite impossible even in my idealised calculation that ignores things like fluid drag.
Can a human survive Mach 1?
If human manoeuvre that speed Mach 1(1225 Kph), the air friction will increase the body temperature enormously. It will almost boil the body. The strange symptoms including temporary vision loss, loss of consciousness and weightlessness. The turbulence causes parts of the body swell out.