Realist said:+1
Gluconeogenesis
It is well known in sports med/ex phys circles that the metabolic effects have an acute positive impact on performance.
That's my understanding as well. One of the benefits for a professional cyclist (although this would appear to be more important for classics or long-days in the mountain in stage races than time trials) is that corticosteroids shift fuel substrate use from glycogen/glucose to fats and amino acids. By sparing glycogen that would make it is more likely to be there in the finale when you need it for high power production.