I doubt |Shadow would even be able to out run this guy. He looks as if he has been working out.
More muscles make for slow runners. Bigger, bulkier "runners" are the runners that just truck out 6-12 miles without winding at all. They can't run fast worth stuff though.
So you pretty much just have to lose the guy. Alleys, bushes, trees, everything can work. Survival of the fittest, not the biggest muscles.