Thanks for all the responses about SuperSlow. In my earlier post, I didn't make it very clear that I was referring specifically to their views on cardio, i.e. that it is unnecessary and possibly even downright dangerous - this is from the link posted by Philip Thrift: http://www.superslow.com/why_not_aerobics.html This site comes across to me as a bit of a polemic and doesn't cite any research. But I find the idea interesting and wondered if anybody knows of any studies which show that the usual recommendation of cardio for 30-50 min 3-5 times a week is not well-founded? Cheers, Jo