Sprint events are short. The lead rider in a team sprint, for example, will be all done in under 20 seconds. A flying 200 will take around 16-18 seconds of effort, a match sprint around the same. Keirins can go a little longer depending on how they get ridden, 500m time trials take around 34-38 seconds and the kilo around a minute.
So we care about the part of the power graph that is primarily and conventionally known as the anaerobic zone. The "ATP-phospho-creatine" and fast glycolitic energy pathways are our main concern. Phosphene runs low in around 6-12 seconds, fast glycolitic drops off around 25-35 seconds (although it contributes for up to three minutes). There is a contribution from our aerobic systems, to be sure, but it is minimal and until you're racing kilos, not the main focus of sprint training.
Looking at the graph above, which is a typical power vs time graph, simplistically we're interested in boosting the maximums that we can get out of our phosphene systems, and our fast glycolitic, and much less interested in the long tail of aerobic power. Our enduro cousins want to boost their aerobic thresholds as much as they can, we're not even vaguely interested in them (especially if there's a chance that by doing so we reduce our peak power outputs and a number of studies have strongly suggested this), our training is therefore vastly different to theirs. We do short efforts, 6-8 seconds long with an emphasis on peak power, and longer efforts, around 25-40 seconds, to work on our 'endurance', or really how long we can hang on to our effort in a longer event. Unless we're also training for kilo or third rider in a team sprint, we will rarely, if ever, do training efforts that last longer than 40 seconds of actual effort.
A recent maxim of Sprint training is this : Sprint training is good for enduros, but endurance (aerobic) training kills sprinters. The adaptations from most aerobic training can be counter-productive to sprint performance ( http://www.ncbi.nlm.nih.gov/pubmed/17190535 ). So we don't do high intensity aerobic training. Enduros are welcome to come and train with us, but we do NOT train with them unless they're on a recovery ride to the coffee shop.