High-intensity exercise that does not rely primarily on oxygen for energy, such as sprinting, is called anaerobic exercise.
“Anaerobic” literally means “without oxygen.” During very intense efforts, the muscles need energy faster than the aerobic system can supply it. They therefore draw heavily on stored ATP and creatine phosphate, followed by anaerobic glycolysis, which breaks down glucose or glycogen rapidly. Sprints, heavy strength training, jumping, and short high-intensity intervals can all involve substantial anaerobic energy production.
Anaerobic does not mean that the body stops using oxygen completely. Most exercise uses both aerobic and anaerobic energy systems; the balance changes with intensity and duration. A short sprint relies heavily on anaerobic pathways, while jogging for a long period depends more on aerobic metabolism.
Anaerobic training can improve power, speed, muscular strength, and high-intensity endurance. It is often associated with lactate production, although lactate is not simply a waste product and can be reused as an energy source. Aerobic exercise, by contrast, uses oxygen-supported metabolism for sustained activity.