Paul Roetert was formerly the Head of Sport Science for USTA Player Development in Key Biscayne. He has been instrumental in advancing US tennis scientifically and shows why here. This book was created for the tennis player and coach and perhaps is the best book on the market regarding conditioning for tennis (there are 3 or 4 other inferior books). For myself, I think it is a bit basic (a primer) and doesn't cover enough scientific applications and how to scientifically create a conditioning program. Anyhow, I think that is for the German DTB (e.g., look up Richard Schoenborn books). Otherwise, Paul and Todd (a top trainer) would limit their audience. The authors produce an excellent resource for most serious players perhaps applicable to all. This book should rank among the top ten tennis books written in the past decade.
Most conditioning methods recommended by even some of the leading lights in tennis have been a regurgitation of methods which was non-progressive and relied heavily on `past, successful experiences'. Afterall, he won with those exercises and practices, so I don't see why .... This book stays closely to the latest research so that the exercises thus recommended are safe, time-saving, objective and practical - the last a criteria for adaptation into actual court strategy w/o too much of a hindrance. Language is simple. Coaches worth their salt should have a serious look at it before dismissing it as another scientific hoodwink by a bunch of scientists who'd never played the real game, except after work.