I will answer your question less pro or con: one, yes conditioning your hands will help you become a better board breaker. Two, yes it does eventually give you different degrees or arthritis, I am living proof,actually right now I'm making a fist and my right hand is very stiff and a little sore when clinched. Although my shins and feet have never been bothered by all the stuff that was broke. Also I never conditioned any part of my feet or shins for breaking either. Probably all the bag work and sparring is enough conditioning for anyones legs, your conditioning them every time you train, how's that?
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The way of the warrior does not include other ways... Miyamoto Musashi Schanne