When I lift weights, I actually tend to gain weight, usually in the area of 115-120 lb. I'll start obsessing about weight lifting a lot then (anxious when I have to miss a scheduled lift day), but it actually keeps my weight up while I still look lean, and I'm drinking the post-workout protein shakes and such. For me, that weight is considered low-normal; though docs tend to be happy with me if I am 105 lb. up. My frame is small too, though it seemed like it was more medium-size in high school. Loss of bone mass? IDK.

I just can't motivate myself the same with dumbbells at home (tried & failed several times), and I don't have anything that would work in the way of a weight bench. Plus, I don't like the feel of the dumbbells we have; they were H's in grad school. Poor H was trying to build muscle; I swear, he weighed around 160 lb. when I met him, and he is 6'4". He's gained some now to a better weight for his height, though he tends to get super-thin by the end of the school year, then gains over the summer.