They love each other by showing that they care for one another.
What doesn't limit the range of moton from the things which you've mentioned would be age. Age per se doesn't really limit the range of motion - while there are factors which negatively influence our range of motion and which are strongly correlated with age, it is hard to say that age itself would be the cause of a limited range of motion.
I’d think it would be a good effect on her parents. Except now their going to need a lot of baby gates!!
Good luck! ;)