Thanks for your reponse. With regards to how I felt, my legs felt fine. As I wrote above, it was rather a feeling of complete emptiness - my body did not respond anymore to my will…
Most likely, altituted played a role in the decrease of power as well but that cannot be the only reason.
I carb loaded the two days before the event and had quite a healthy breakfast, approx 100grams of oats with one banana, some berries and two slices of bread with jam.
Also, I usually do at least one fasted ride per week in the early morning of 1.15h-1.30h in hope to improve my fat burning engine.
Concluding, I really do not know what my limiter was - possibly overpacing? Should have maybe gone 20 watts slower up the Jaufen?!
@Brennus: does the amount of carbs I can store in my body depend on weight and height? Reason is that I weigh only approx 64kg at 180cm. Can one extend the amount of carbs the body can store.
Cheers and thanks for the interesting suggestions!