Oops forgot to put this post on my tracker only just saw the reply. I can't find an official site that says 400 cal, but a government site here in Australia says 100 cal every 10 mins http://communityed.education.tas.gov.au/course/HULA1 hope this helps, and we can see hula hooping on the tracker soon =)
Thanks for the suggestion. We would need to be able to verify the calories burned on an official government site. Do you know where you saw the 400 calories for every 30 minutes? If you can find this information on a government site, we'd be happy to add it for you.
Thanks,
MedHelp