Yep, because the person lifting heavier weights will have larger muscles due to the stimulus of heavier weights. Does the other subject that never increased weight increase repetitions? The individual lifting lighter weights would not be as strong, but would be better conditioned if he/she increased the number of repetitions.

I just looked at this article:
http://sportsmedicine.about.com/od/a...eFiberType.htm

There are links to other interesting articles near the end.. I am going to read up on it when I get the chance.