ORIGINAL: BobCo19-65
I'm sure it will make you strong. Don't forget about the other way also. Personally, I can get my form more perfect with a lighter bow (30 pounder). After I get the form burnt in I go to the heavier bow.
Sometimes I notice shooting my light recurve, I almost have too much control if that makes sense. Especially on my release. I like shooting them all. I do believe the heavy longbow kinda keeps my muscles in check and conditions them.