I followed Vogue on Instagram until recently when I unfollowed due to too many #ads. She's awesome though, really sound. Rock of common sense. No drama whatsoever.
She works out every day. She worked out most days during pregnancy when her sickness wasn't too bad. She did adapted pregnancy work outs and then she had an easy birth and didn't tear (according to her, lucky bitch) and was able to back training quite soon. Breastfeeding too!
So it's not really genetic there, more she's sporty by nature. She must have a lot in common with pippa.
I do find those pictures horribly invasive but it is a public beach. After the first day I'd have never left the pool, tbh but they mustn't mind that much if they went back another day.