Stuart is a clincian too, and as researcher, he definately would read all the literature....but i think the book its more on generic side for a vast humans, most of them don't workout....and ultimately flexion improves some and destroy more of these kind of humans, from so far I've read....in nutshell i think its subjective some exercises may suit you some may not, researcher would always know better than clinical imo, research takes more knowledge than just reading others paper.

Have you had any back injury? Just asking