Dogs speed, an estimate, about 5 mph faster than said cyclist for the first 5 yards, then the cyclist's heart rate comes into play. It goes from the normal average rate for his riding cadence to about 10X that figure, thus sending enough adrenaline to the legs for a burst to say 45 mph for maybe 1/2 mile or, until he explodes, and the dog begins to lick his face as he lays there bleeding and panting.