Muscle has to be TRAINED to become hard - otherwise, the effect is strictly cosmetic. If that's all you want, well - there you are.
However, this points up the fact that *size* does not equal *strength*.
Another suggestion that folks drill thru the archives here: the is SO much info available. In this case, there's been a lot of talk about guys who just take 'anabolics' without putting in the sweat-time under the iron to really build a physique: it makes them 'big' - but soft, and deceptively weak.
So: if your muscles are big, but soft, you're not working hard enough for what you've got.