What does workout and physical resistance mean in bed?

I know, I know what are you thinking: silly question. Ofc, sex is a physical activity so it counts, but what I mean for really is: does physical resistance influence the time of the male performance?
I always see “bad boys” and pstar workout and I was asking myself: “does it increase the time for a man needed to cum or is it only for appeal?”

You grow up, you got a dick and you gotta take what is given to you, but is performance (time of recover, time of the erection, time of sex, ecc) part of genetics too?