someone on another site posted the following and i disagree. is he right?
There is really no correlation between size and strength. Some wiry people are tremendously strong and many bodybuilders have very little functional strength. The kind of whole body, core strength that is required for riding (and most other athletic activities) can be gained without much muscle bulk.
To gain a lot of size takes a very focused regimen of exercises designed for bulk and not strength and diet to pack on mass. If you don't do this, you will not gain a lot of size. Good, hard strength training will develop some muscles, but not huge size. You would just end up looking more athletic and toned from it.