Scenario A: athlete A trains their AWC extensively, upregulates the glycolytic pathway and downregulates the oxidative pathway and the fatty acid system. When they go race they’ll have to rely on their AWC to finish
Scenario B: same athlete trains all CP and sees the opposite occur.
Knowing that this book is primarily about swimming and that it was published in 2000 helps frame where it stands. In 1994, we got “swimming fastest” which went along with an idea at the time that mostly all you really need to do to swim well is train at “lactate threshold.” Where in this case lactate threshold meant 30 minute pace. That this was the magic effort that would maximize performance for a given training time. In 2001 we got “Lactate Threshold” training which expressed a similar idea for a multitude of sports.
The Jan Olbrecht book sits as counterpoint and in fact Ernie Maglischo states as much in the foreword of the book. So it was at the time very important to drag swimming in particular and endurance as a whole away from the single magic pace idea.
Obviously the single magic pace idea wasn’t one that was universally adhered to, the Peter Coe Training Distance Runners and Daniels’ Running Formula are counterpoints - though obviously in running.
So as a piece of work and where it sits in the popular literature of exercise science - it’s definitely a solid book.
However you and I aren’t the only people to come across its concepts and give sidelong glances to the idea of direct inhibition of aerobic capacity by anaerobic capacity (bearing in mind that “anaerobic capacity” is probably not the best term to use here). As an outcome of training volume, sure spend a lot of your minutes training your anaerobic system and we expect your aerobic system to suffer since you only have so many minutes to spend in a week on anything period.
I’m no sport scientist, but for me I don’t really buy the direct inhibition part of it - that you can make your anaerobic too strong to use your aerobic system effectively. If in case 1 I spend 8 hours per week running aerobically and in case 2 if I run 8 hours aerobically but add another 90 minutes of intervals i find it hard to think I’d be slower once I acclimated to the stress.
Nevertheless in real life, it matters little. To really get the most of our performance, we need to work both systems in the appropriate amount. Appropriate is a big word in this case though. When considering swimmers in 1999, we are mostly considering people competing in the 40 seconds to 2 minute range with a few out in the 5 to 20 minute range.
The “appropriate” amount of anaerobic training for an ultramarathoner or iron distance triathlete is likely to be a wildly different number. And finding that appropriate number is the tough part.