As to weigth and climbing, if you loose wieght too fast you may (probably) loose more muscle than fat, with steroids this effect would be negated. If you wish to do a test to see how good you would be at a lower wieght try pulling on a hold you cant pull on normally but with 4 kgs taken off with a pully and weight, you will be shocked.
I see your point completely and a la le sausage I can't see that being a particularly bad thing if you've got a bit of leaning out to do. What I fail to comprehend (or don't wish to believe) is that you will see the same increase in performance as you reduce the weight even further (to a level that makes you ill). There's got to be a point where it just doesn't get you anywhere, yes you might be able to hang a micron wide edge but energy levels and recovery surely suffer and hence make the whole process a waste of time (but you didn't find this to happen?). I guess this point will be at an earlier stage in bouldering where power is more of a focus compared to routes.
Completely agree, the catabolic state of the caloric deficit will render musculotendinous injury at some point (varies by age/training age) making the A.N. condition at odds with climbing performance (although I agree that clipping bolts will probably favor the A.N. over bouldering).
At the recent Bouldering World Cup in Vail, the female Finalists (Euro and American) didn't appear to be in unhealthy BF conditions. The shift (in the States) from sport to bouldering, I think, has taken the edge off of extreme weight management. It seemed like the top female competitors of the lat 90's were unusually lean, and today's competitors look more athletic.
The climber who has decided to cut weight (short term, as per the example of 3 weeks) is playing a risky game in relation to performance. Is the cut weight water (does that person normally retain water, if so fluid loss may be a benefit, if not, then they should expect a performance deficit) or lean mass (is the lean mass from the chain of climbing specific musculature...depends on the anthropomorphic features of the individual) or fat loss (generally of benefit, but unlikely in such a short term without risking lean mass loss)? Loss of lean mass may not be a big issue as climbing performance is closer to neurological upregulation and tensil strength than large muscular cross-sectional diameter strength...some balance must be had. Some hypertrophy is needed for performance and some is needed for structural integrity to avoid injury.
