Anyone tried these? During an unintended shopping spree on the internet I bought a set of these bands. I haven't used them yet but I want to improve my core strength so I'm going to give it a go. I am slightly worried that they might ping off my foot but other than that there seems to be a wide variety of different exercises you can do with them. In my dreams I'm seeing myself with a 6 pack in a few weeks. In reality I'm hoping for better posture which will help my running.