The default is to rebuild indexes off line any way. While this may reduce
some of the logging activity that will not be the deciding factor in how
much gets logged. If you rebuild then indexes you can change the db to
Simple recovery mode beforehand to minimize the logging. But you will need
to set it back when done and issue another FULL backup to restart the log
chain before doing log backups again. You should ensure there is plenty of
space on the drive to do what needs to be done. If you are rebuilding every
index in every table you can do one of two things. One is to run several log
backups during the rebuild process to allow the space to be reused and keep
the log file size in check. But You should really not be rebuilding indexes
that don't need rebuilding in the first place. Stop using the maintenance
plan and create your own job to only reindex indexes that have above a
certain amount of fragmentation. That will greatly reduce the number of
indexes that get rebuilt each night and thus less logging. You can find a
sample script in BooksOnLine under the sys.dm_db_index_physical_stats entry
to rebuild only ones that are above a certain fragmentation. Or have a look
at this article in SQL Magazine with a sp to do that and more as well.

http://www.sqlmag.com/Article/ArticleID/99019/sql_server_99019.html