This is a book that does not promise you a miracle, but that helps you gradually you move a bit! The program is very well thought out, about 4 weeks, at 6 sessions per week and four exercises per session (one stretching). It comes with good advice to motivate you and / or help you take good habits. The least we can say is that we feel the muscles work, if you follow the instructions, but it's far from a penance sessions are short and we feel the benefits in provided they are regular. For those who want more, I advise in the same series and the same author "The abdominal lazy-butt".
