I've never had a problem with it - I guess you need to find the right sized one. Also, it's a strong stretch and one can build up to it using a rolled-up towel

I've never had a problem with it - I guess you need to find the right sized one. Also, it's a strong stretch and one can build up to it using a rolled-up towel and use it on all parts of the spine. I just go by feeling. I actually got mine from a chiro - there must be a precise diameter required for the spine - 14.5cm hard foam.