Did you ever notice that there is an abundance of physical comedy in silent films.
Yeah, it seems that, even then, the absence of dialogue forced an alternate form of attention-grabbing style to be necessary.
It makes sense that the limited technology of the day forced the star to actually do his own stunt work.
Plus, each of these stars were always trying to out-do each other.
So, multiple cameras, stunt men, insurance policies, and CGI are all examples of the way physical demands changed for actors.
But those early performers should always be admired for their impressive feats of physical skill.