Pilates with machines
I just started doing Pilates in private sessions at a studio that focuses on Pilates, Gyrotonics, and Feldenkrais. They offer both private sessions and classes with four students. All the instructors are trained by Polestar, which seems to be a rigorous program. I did some Pilates on the reformer with my physical therapist, and even she does not hold a candle to this amazing instructor I'm working with now. I've really been blown away in my three sessions so far, and honest to goodness think Pilates is going to change my life. Fortunately, my medical insurance is covering part of the cost for now.
It seems to me that the mat class is very advanced--there's no help from the reformer/trapeze machine, etc. I think it would be difficult to get the full benefits without assistance because one would be concentrating on just completing the motion instead of concentrating on form. It would be the equivalent of hefting very heavy weights your first time out. There is soooo much to keep track of in Pilates--breathing; the exact position of your spine, chest, shoulders, hips, neck and head; doing the motion, activating the right muscles, etc. that I can barely do it even in a private session with someone right there to remind me. It really is training your body to hold itself in an entirely new way. It isn't just about abdominal strengthening, but also increasing your range of motion, strength, etc. with good alignment.
MHO is this: I think anyone doing a mat class or a video could get significant abdominal strengthening, but I don't think you could get the full benefits of Pilates without a lot of instruction and individual attention, i.e. in a class no bigger than four people.
http://www.plauder-smilies.de/pyth.gif Gretchen