Calligraphy has power. Does it mean that the strokes of writing have power? Do the arms and wrists that can write have the strength to write?

This formulation is wrong.

Are you talking about the ingenious effect of calligraphy lines?

The expressions related to qi in calligraphy are "momentum", "verve" and "strength".

People who often write have a persistent "persistence" in the process of writing, which is a kind of maintenance and a feeling, a bit like the qi in Qigong. It cannot be simply understood as strength.