What Depalma said.
The whole "tone" thing - lift light and do a gazillion reps - is quite simply useless unless you're just wanting to raise your heart rate. In which case, just do regular cardio.
Toning is a myth that is pushed on women who have a fear of getting muscle bound. But the truth is that you're either building muscle or you're not. There's no such thing as "toning" in that sense.
The only way to fill out that empty skin (as the fat leaves) is to build muscle to take the place of the fat. You should do triceps and biceps and lats exercises ... as heavy as you can lift. You should ideally be able to just barely complete 3 sets of 12-15 reps (with 60 sec rests between sets).
Don't freak out about "bulking up" either. It's nearly impossible for women to really bulk up without actively trying (i.e. protein loading, really really really pushing the weights, etc.). We just don't' have the right hormones and muscle composition to "bulk" the way a guy does.
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