Julie,
We had a good discussion on this a little while back...
http://www.breastnexus.com/showthread.php?tid=23762&highlight=strength
Loss of strength is a given, we're wondering about how it works.
The muscle mass isn't reduced the way the strength is, though - muscle mass is removed over time, strength can drop off rapidly.
To maintain strength, you need to keep working out. It's personal checks and course-correction that will get you where you want to go. Same as NBE. ;-)
The one big thing is, you won't be able to build mass too well. It's also easier to retain strength than to build it.
Other threads of interest:
http://www.breastnexus.com/showthread.php?tid=24163&highlight=strength
http://www.breastnexus.com/showthread.php?tid=14442
http://www.breastnexus.com/showthread.php?tid=22772&pid=140896
Probably others, too - I just grabbed a few I knew off from doing a search on "strength" in the NBE for men subforum. ;-)
-Jean