i heard of this, it's not really a hack but an exploit if it's the same situation i seen online. if timed correctly, people can run a lot faster. dunno if it's the same deal.
Check this out, specially if you play GOW online
"A so-called rumor on Maxconsole is supposedly being circulated about whether or not people have found a way to mod Gears of War. Well, if you were to ask me I would say yes. I have had first hand experience with this, because I have gotten the unhappy pleasure of playing a ?ranked match? with one of these bone heads less than 24 hours ago. To make matters worse he was spewing racial obscenities nearly the entire time. If as his dirty mouth wasn?t enough he began doing some crazy things that were clearly not intended by Epic.
Firstly, he began running around the map at superhuman speed. Almost to the point were you hard a very hard time even keeping up with where he was at any given time. Secondly, he was able to roadie run and fire at the same time. Of course, every one in the match filed a complaint against him, but the real issue here is why does anyone want to do this in the first place? Ranked or not, this ruins the experience for everyone. Hopefully this doesn?t become the next Halo 2. While Bungie has handled this relatively well, I would have thought this was a thing of the past. Maybe not."
From Maxconsole (via Xbox Scoop)