golfer: It’s not supernatural. A shliach tzibbur paces himself and knows what his limitations are. In the 1990’s I used to walk 1.5 miles to be a shliach tzibbur for shacharis and mincha for a small shul and then walked back the 1.5 miles to daven neilah with my family.
It was much harder for the Kohen Gadol to the entire avodah by himself then to daven fo the amud.