If you did it in the olde fashioneded way with a manual hammer, manually stoking the forge with a bellows, etc., then sure. But AFAIK modern blacksmithing is pretty similar to modern carpentry or welding or any other hobby where the machines do most of the work. It’s still a somewhat active hobby, compared to doing something with a computer. But, I don’t think a modern blacksmith is going to get huge arms from doing it.
If you did it in the olde fashioneded way with a manual hammer, manually stoking the forge with a bellows, etc., then sure. But AFAIK modern blacksmithing is pretty similar to modern carpentry or welding or any other hobby where the machines do most of the work. It’s still a somewhat active hobby, compared to doing something with a computer. But, I don’t think a modern blacksmith is going to get huge arms from doing it.