Given the way nature ‘works’ I’d bet there are some small portion of the population that legitimately can’t get AeT to within 10% of AnT or move MaxVO2 by any measurable amount but the population numbers are likely tiny. We’d have to capture more globally sourced information as well as wider demographics to be more sure… Granted, every individual’s metabolism responds at different rates but literally everyone we have worked with who has properly tried long enough* (proper training, testing, some diet changes, etc) has affected their metabolic curves in the direction benefitting their goal and it seems impossible most of these individuals are ‘gifted’.
We have seen marked, and in some cases large (~doubling), increases in ability to sustain workload and intensity at lower heart rate using treadmill-based tests. “Seeing” this can be done in the lab, or on a treadmill using our testing protocol, or hiking/running up a test slope. Testing on terrain similar to one’s goal shows the intersection of one’s capacity for work specific to the terrain/equipment/environment AND the metabolic response to that work. These increases equally applies to the 95% of our coached athletes who do not start as well-trained as they do to the 5% who are well-trained. And, like the emails Scott mentioned, I would suspect the same would apply to those we coaches don’t see.
Keep in mind that for some the initial goal, after testing and training for enough time, has needed to shift from it’s initial iteration based on response rate or limitations of other performance characteristics. Often we see change on the order of time; another year of endurance training is needed to be in shape for the 50mi run at a goal time, but the 30mi this year is more reasonable, etc. Further, targeting a singular metabolic goal, like only increasing pace at AeT and doing no work above AeT, can lead to declines in other characteristics like pace at AnT so that in the short term the structure of said metabolic curve might not look like the long-term goal metabolic curve. However, that is an easy fix with a relatively small amount of volume at high-intensity while maintaining an amount of base endurance volume.
So, addressing the functionality and ‘trainability’ and ‘achievability’ in terms relevant to your goal, as well as joining onto Scott’s points; we have to look at the athlete holistically as well as the goals. Achieving a higher MaxVO2 for a 30mi run is very much less important than it is for the VK runner. We have seen positive responses to training stimulus, measured by AeT and AnT, for the functionally everyone who trained long enough, no matter their gifts.
Great question!
-Seth
*6+ months of consistent training
