In reply to m@:
Seem to remember seeing Pete Botterill of one of the others from the Carlisle team in the late 80's using it for doing circuits on the Cockermouth wall. It wasn't a full weight belt, just a belt with about 5kg of small weights.
Seem to remember he was one of the elite lads at the time, and it didn't seem to do him any harm.
Then again he was training for the hardest TRAD routes of the day and carrying a full rack of gear, as opposed to bouldering for the sake of it, or doing sport routes with nothing more than a few quickdraws.
I for one wouldn't call guys like that stupid !