DD was mellow in terms of her personality, but the girl is/was a physical dynamo. She was all fine and good until mobility, she crawled and cruised at 6.5 months and hasn't really mellowed out until now-
she's 3.5 and still she's on the upper ends of activity level

. I guess I knew she'd be like that though, when I was pg the girl would give me roundhouse kicks that would show all the way around my stomach. I spent most of DD's toddler years trying to keep her alive. She just ran and ran, and then ran some more.
Now DS(6 months) is very similar in ways physically, he is army crawling, moving, rolling but his personality is more easy-going than DD was in certain ways. I think with him he'll be active but not in such a dare-devil way, it's weird he just seems more cautious than DD ever did. Maybe I'll be wrong, but something is telling me that he'll just be more mellow as a toddler. Honestly I also think he won't be so dramatic, more chill.
I don't think that the two correlate-at least not in the children DH and I create. Which isn't surprising, we are mellow(personalities) and pretty active at the same time.