Is 'Tini has a strong arm' really a good translation for this? I feel like 'Tini has strong arms' is what would be understood in pretty much any context.

the speaker says "punya lengan" so quickly that it sounds like one word and thus difficult to understand

It seems like I hear tangan used frequently for both hand and arm (and kaki for leg and foot). Is it better to use lengan though for arm?