No mention of that
Here,
Here or
Here
The two recent times he's been knocked out, first against Speed Demon, and then against Spider-Woman, Luke Cage, Spider-Man and Wolverine really don't demonstrate he's powerless when he's without the crowbar, as both times the crowbar was used against him, a crowbar that grants the user tremendous strength along with the strength of the crowbar itself, and it was used by super-powered people with their own stregths.
Speed Demon hit him MANY times, Flash style, until he went down, and against the New Avengers it took the combined forces of the four I mentioned above, and then after they got the crowbar from him, Spider-Woman hitting him with it, and THEN Luke Cage finally knocking him out with it. Luke Cage ain't no slouch, that combined with the crowbar, it took a lot of effort to knock out a 'supposed' powerless, regular joe named Dirk.
From the facts it seems like he IS super strong and durable without the crowbar, just more WITH the crowbar.