After longer than I care to admit I have reached the 95th percentile body fat percentage called out in the Racing Weight book. Taking guidance from the book I am ready to move to the performance measures.
The book calls for running 10km at 95% maximum effort to establish performance metrics. I assume this to be a heart rate measure.
What does it mean? Are we expected to run at 95% threshold heart rate or 95% maximum heart rate (which takes me into zone Y)?
The idea with the relaxed 10K time trial is to cover the distance literally, mathematically, about 5% slower that you would do in an all-out race. So if you estimate that your current 10K pace is 8:00 (480 seconds) per mile, aim to run the relaxed 10K time trial at 8:24/mile, give or take.
Not quite. What you’ve articulated is more reductive than what I recommend. The relaxed time trial (and it doesn’t have to be that–it could be any relevant performance test) is just meant to serve as a check against losing too much weight or losing weight the wrong way. But the pass/fail concept is too simplistic because your 10K time could fail to improve for a lot of different reasons that have nothing to do with body weight/composition. The most important thing, I think, is to remain process-focused. Eat by the book and train by the book and you can trust that, overall, you will move in the right direction in terms of body weight/composition and performance.