"Street fight" is a cliche expression, I guess you're supposed to imagine tough guys in the city duking it out for territory? Well guess what, they use weapons for that.
Lift weights for 10 years until you're 300 pounds of pure terror, and then some sneaky little runt runs up and stabs you in the gut, and you can't catch him because you're a big fat gym rat, explosive power or not.
If you had to battle Mariusz Pudzianowski in an unbounded arena, such as an open plain, he would constantly be on defense. He couldn't outsprint you, so you would dictate where and when the actual combat happened. The best he could achieve would be a draw. He would be doomed like a tarantula battling a tarantula-hawk wasp.