Fats and carbohydrates are the two main sources of aerobic energy. Lactate is a by-product of the anaerobic glycolytic system and a fuel for the aerobic system. Even though lactate is not involved in the creatine phosphate system, the presence of large amounts of lactate while training this system is an indication that the creatine phosphate system is reaching its limits. Also increases in lactate during aerobic training means that less fat and more carbohydrates are being used as fuel. This system produces short, very intense bursts of energy, such as for sprints.
Creatine phosphate is broken down very quickly and produces energy extremely fast.
It is an anaerobic system because it doesn't use oxygen. It is frequently called the alactic anaerobic system to contrast it with the other anaerobic system that produces lactate. Weightlifting, jumping, throwing, and short sprints depend almost entirely on the creatine phosphate system. Frequently, coaches will have their athletes conduct sets of very short sprints to develop this system. In competition, creatine phosphate lasts only a few seconds.