One of my good friends, Joel Jamieson, from my early days in strength and conditioning at the University of Washington sent me his products a few weeks back. He is the author of Ultimate MMA Conditioning, as well as The Ultimate Guide to HRV Training. Joel runs a website at www.8weeksout.com. It has a lot of great information as well as a forum for those in the sport of MMA to talk programming and trade ideas.
When you really want to know how the body's energy systems work and interact with each other, look into Joel's Ultimate MMA Conditioning. It's so much more than an MMA piece. It covers details and principles on each of the energy systems as well programming principles to get you started. The great thing about this book is it isn't a "copy and paste here" program. He outlines principles so that an athlete or coach can integrate the material into their own program. Athletes in generally, but especially in the case of MMA training a one size fits all does not, and should not, apply.
I firmly believe this is the single best source there is on energy system development. The single most visible weakness for interns entering our program is the ability to understand and program energy system training for athletes. Too often the "strength" side of the "strength and conditioning" is all anybody thinks about but its the biological power of the body to produce the necessary amount force, or speed, recover, and then perform this cycle over and over again over long periods of time that is important.
Joel gives a great overview of why the aerobic system is so vital to the ability to recover and why it actually is so important to the alactic system in the grand scheme of things. Another great thing Joel reinforces is that training does not occur in a vacuum. Skill development as well as the physical preparation in the form of strength and conditioning must coincide and be in harmony together. Although this is geared towards the MMA athlete the principle remains the same for everyone. An athlete can't train "strength and conditioning" with one coach for 2 hours, then go train with another coach on skill work for another 2 hours when coach 1 has no clue what coach 2 is doing and vice versa. Everything creates stress on the body and when this stress becomes too much, the body breaks, in the form of injuries, sickness, etc.
I could create a week-long lecture on the benefits of Joel's manual and some of the issues that it brings to light in the field of strength and conditioning. I do believe that he's put together a great resource and recommend it to anyone who really wants to know how the body works.
I've touched on a few of these topics before and here are some related links: