Yup. Same principle at work and valid ... with caveat.
All conditioning methods are painful. Period. The only way to build up the bone (or muscle, for that matter) is to break it down a little bit. The physical conditioning/strengthening actually happens in the resting period between workouts. As the body heals these things it strengthens them. Over conditioning will just lead to deterioration because your body never has a chance to rebuild.
Also, there is a psychological component to conditioning. You get used to the pain at a psychological level and your pain threshold rises. That can also be useful.
Caveat: One of my instructors has done *a lot* of conditioning in his life. He says, "I don't recommend it. The fact that I can still write my name legibly is due more to luck than anything else. I know many contemporaries who were maimed by the conditioning. Even if they're now able to spear hand through concrete their hands are only good for destruction. They can do no fine work."
An addendum to the caveat: The forearm conditioning I've done was all done with another person (i.e.: banging our forearms together). I think this method is preferable to conditioning on inanimate objects (though I have maintained my conditioning on inanimate objects). I think that conditioning on another person has some built-in safeguards against over conditioning.
Just as you can pinch yourself much harder than you'd let someone else pinch you I think, with inanimate objects, it's much easier to drive yourself too hard. When working with another person you generally don't go as hard because you don't want to hurt your training partner. I think this means a more gradual conditioning which minimizes risk of over conditioning and injury. I think, also, that the more gradual conditioning can lead to more thorough conditioning but that's totally my opinion.
Based on empirical evidence in my own conditioning and dealing with other people who've done different conditioning I personally think conditioning on another person is preferable to using inanimate objects for initial conditioning.
Mike
