Before starting transition, it made me feel a bit nervous. It still does, sometimes.
I'm not very physiclaly active, and I've never been in a real fight in my life, but having strength is convenient, and knowing that I could theoretically fight was what finally gave me the confidence to stare down and intimidate bullies in high school. Transitioning is could get me some negative attention, and I'm not thrilled about the prospect of facing it with reduced fighting ability and running speed. On the other hand, I don't know anyone around here who has been bashed, so I think it won't be a big issue.
On the bright side, family members are less likely to rely on me for moving all of the heavy furniture. Also, I hate feeling bigger and stronger than the women I date, and it was nice to date a lady who was stronger than me for once, a few months back. She was soft butch and worked out a lot, and probably was as strong as me at my prime, so it felt really nice to be held by her and feel safe. Rather than always having to be the "man" being protective of "his" woman, like both of my girlfriends had been before I accepted that I was trans.