I would suggest that if somebody is determined to use a video, they should at the very least go to an instructor for a few lessons to understand why or how to do the things that are shown on the video. So often the video just shows people doing things without explaining how to get there. You'll see a person lying on their back with their legs up in the air and might interpret that as the hundred pose. The 100 is probably the most well known Pilates exercise, but if you don't understand the reason you're doing it and what kind of position your body should be in, you're not going to get any benefit from it all and may even injure yourself (or even worse - look ridiculous). It's very important for you to understand the principles behind the art in order to see a video and understand proper positions. I can make corrections with my clients that are as subtle as 1/4 inch and they will feel the difference. It's surprising when I look into the mirror for certain parts of the session and see that they only think they're doing what I'm asking them to do. It's such an unintuitive kind of process.
