My 2 1/2 mnths baby girl is very playful and moves and move a lot, i just notice that she can twist her arms a little bit, is is it normal?

Her doctor needs to : See what your talking about to answer your question. Hyper extensible joints & low muscle tone run in some families who are otherwise fine. Sometimes these physical findings can be associated with known genetic syndromes & other medical causes of developmental delays. Firstsigns.Org has developmental screening tests. If you complete one for her age, take it with you to her check-up.