Hi, i brought the ab circle pro as a present for myself for my 29th birthday and it was the biggest mistake i ever made! within the first month of using the machine sporadically my lower back started aching. Had scans done on my back and i have bulging disc through my whole lumbar area. I havent had a pain free day since. It has completely ruined my quality of life and the enjoyment of time spent with my 4 young children. Every time i have visited a health professional they have asked my what had happened but i havent been able to pinpoint anything. It was only last week it clicked that all these problems came about after i started using the ab circle pro. Needless to say i'm back off to see them next week for a medical opinion on the cause of this problem. I want to start a class action cos this machine has literally ruined my life. Its been almost 12 months now. To those who are experiencing back pain STOP using it and go straight to the doctor!