The above diagrams are based on IEC electrical safety related standards and in my case more specifically on publications of Prof. V.Carrescia teaching “Electrical Safety” at the Polytechnic of Turin, Italy.
Considering the very low currents involved I don't think there are big differences between DC and AC, except for body resistances/impedances varying according to specific frequency.
However here below some actual measurable numbers:

50 km/h is 13.9 m/s (50000m/3600s)
13.9 m/s is approx 6.3 rps (rotations per second based on a 28” wheel)
6.3 rps is approx 82 Hz based on a 26-poles hub dynamo