I really don't see how anyone could run 16km in a game, at least not whilst refereeing it properly. They'd have to average running 10.7 km/h over the 90 minutes, and there will be lots of points where you can't run at all.
Even in the fastest game I ever refereed, an EFL U23 game on a huge pitch that was completely end to end, I only got to 12.5km. And back then I was very fit and got a lot of praise for how I was always on top of decisions in that game, but I was completely drained after and had nothing left in the tank.