Just recently received by email (22nd July 2009)

I was one of the four women that wrote the XBX. We were all in the Royal Canadian Air Force; only in that setting could the XBX book become a reality. Every two weeks we would have a class of fifty plus Trainee's, they would be with us for two months. Every week they would be tested and we would stop/change/adjust an exercise to obtain better results. This went on for over a year. We invited Older women (fifty plus) to take part. Bonnie Pruden also had an input in the book. The book was not done just for a fitness book but rather too improve the ability of the Airwomen to carry out their duties and enjoy their R&R. XBX comments.

IMPORTANT NOTE: The XBX plan includes an exercise - shrugging shoulders - . I asked Chris Duncan about this and his comment was : "I'm not a huge supporter of shrugs as it requires an weighted rotation of the joint."

Important note on slimming using 5BX,XBX. Both programs recommend other physical activities outside 5BX/XBX to develop fitness level and especially to burn fat. (I am walking now about 5 days a week - probably about 3 KM) There is a good article I found on the net on this and then promptly lost it ! However I got an email on 6th Spetember from Angelo that is worth a read.

Hi Chris. I was just remembering of something. From a study made in America many years ago, I've been aware for a long time that when you do some exercise your body doesn't start burning fat before at least 20 minutes. That's because it burns first the glycogen from liver and muscles and then carries on with the deposits of fat.

I just wanted to make sure you knew that (but maybe you do already) to let people reading your site be aware of the fact that they can't rely on the simple XBX [5BX] program (fabulous to get toned and stay fit though) and a diet to really lose weight. As for me, since I like jogging and cycling, I do it at least 3 times a week never less than 40 mins as a supplement to your program.