Additionally being bipedal means that as we run our breathing rate is separate from our gait. As four legged animals gallop the motion of their running expands and contracts their diaphragm, forcing them to breath at the same rate they run at.

Since they can’t sweat like us, or breath like us, they have to stop running and start panting in order to cool down.

While humans can just keep going, relentlessly, like the It Follows monster.