or multi-joint (& multi-directional) movement training does appear to have considerable merit. Isolated muscle development vs functional training is much akin to the difference between bodybuilding and true (functional) strength development. As per your recommendation, I "google browsed
" thru Mike Boyle's book -- he makes excellent points about training for the specific demands of a given sport
and does a very decent job of covering many facets of functional training.
However, I remain unconvinced that muscle imbalance
is an issue that can ignored. There appears to be on-going debate
in the exercise community about this particular aspect. Some advocate a training program that focuses on both movement and muscles in order to correct muscle imbalances.
In browsing thru Boyle's book, I noticed that he does recommend some "isolated muscle" training. It is also interesting to note that so-called isolated muscle group training, especially with free weights, is not really isolated. For instance, in performing a biceps curl, the forearm & hand muscles hold the load, the triceps muscles passively stretch, the shoulders inhibit unwanted motion and the core stabilizes the entire body.
Nonetheless, I applaud you for bringing up the subject of functional training so that we can all be further enlightened on proper training for tennis.