Originally Posted by SFV Rider.
I definitely don't look or feel fatter than I was before, and I’m definitely in better shape than I was 4 months ago.. Is it possible that I gained 10 pounds of muscle in that time?
No, it's not possible to gain 10 lbs of muscle in 4 months. Unless you use the Barry Bonds method.
A pound or two of that extra weight may be fluid. Your blood volume increases when you become aerobically fit.