Getting back into cycling after a decade or so break and treating myself to a nice bike I thought would upgrade to clipless pedals. I got the Shimano 530s and a pair of Vittoria MTB shoes and on my first attempt after a few minutes in the park I fell over. D'oh! This happens to everyone I thought, so after dusting myself down I tried again and fell over again. The second time my foot was still stuck to the pedals as I was lying on the path and I had to take my foot out of the shoe before levering the shoe off the pedal. After a couple of weeks I tried again, being careful to clip in only one foot at a time. Most of the time this was successful and I thought I was really going to enjoy this clipping in business but then my foot got stuck and only got unclipped after a good deal with to-ing and fro-ing. This happened with both feet. A lot of the time I would clip and unclip easily but sometimes the shoe just jammed on and I don't think I was doing anything differently. Does anyone know whats going on here? A duff pair of trainers and/or pedals?