Muscles!

Sclosages

I have noticed, that muscles I would have had strong before are easy to build up again. Other muscles, in places I would not use often are hard to build up.
It's like the muscle is there, just waiting to be used, in the case of my legs for e.g., but my arms, just seem like they are the size they are and that's it. Does that make any sense?
I'm female btw.
Is it slower with lesser used muscles from the past, or will they never become strong?

Sclosages

Sorry, my English leaves a lot to be desired there.

Strong legs, lots of muscle from young age, out of practice for months, 2 weeks, muscle restored.
Weak arms, never had muscles, nor built them up in arms, out of practice 2 months, muscles like a kitten's still?

Blacktie.

It's called muscle memory. If you've gotten trained before then you can build back to where you were much quicker than if you started again. It will take time for untrained areas to catch up but if you keep at it and your diet is right they will grow.