And this (from a running article, so still leggy):
The contribution of the fast glycolytic system increases rapidly after the initial 10 seconds of exercise. This also coincides with a drop in maximal power output as the immediately available phosphogens, ATP and especially PCr begin to run out. By about 30 seconds of sustained activity the majority of energy comes from fast glycolysis (2). At 45 seconds of sustained activity there is a second decline in power output (the first decline being after about 10 seconds). Activity beyond this point corresponds with a growing reliance on the oxidative energy system.
Funnily enough, looking at my ilevels chart thingy, for the season, my Ae/An cross-over is exactly 1:00; for the last month it’s ~0:45…which lines up nicely with interval results. Damn science!