Practicing yoga is certainly something that is done in silence and therefore this image conveys that very well. I do feel that the image is a bit too dark and also that you cropped it a bit tight. 5
The concept is great. I just don't quite like how her pants blend into the background. Also I think if there was less shadowing on her face it would be nicer. After all yoga is all about finding the light, now isn't it (: