Energy Systems

The Three Basic Energy Systems: ...

  • Anaerobic A-Lactic (ATP-CP) Energy System.
  • Anaerobic Lactic (Glycolytic) Energy System.
  • Aerobic Energy System.


1. Anaerobic A-Lactic (ATP-CP) Energy System

      The anaerobic a-lactic (ALA) system, also known as the ATP-CP, or adenosine triphosphate - creatine phosphate system, provides high bursts of start-up energy for activities that last less than ten seconds in duration.

Athletes who compete in sports that require high amounts of short duration acceleration - SPRINTING SHORT BURSTS SUCH AS 5 - 10M lengths, shot-putters, weight lifters, gymnasts, or sprint-distance speed skaters use the anaerobic a-lactic system. The ALA system does not create energy for sufficient duration to create a great deal of waste products.

2. Anaerobic Lactic (Glycolytic) Energy System

      The anaerobic lactic (AL) system (also known as fast glycolysis) provides energy for medium to high intensity bursts of activity that lasts from ten seconds to two minutes. 

middle distance runners

       (400m-800m) and 


       rely on this system. The anaerobic lactic system, as well as the ATP-CP system, are capable of high intensity levels, and do not rely on oxygen for fuel.

The primary difference between the two systems is in the capacity of the system. You can think of capacity as the amount of time that the system can work at peak output before dropping off.

Whereas the ATP-CP system will only produce energy for 10 seconds, fast glycolysis works at capacity for as long as two minutes. As a result, waste products such as lactic acid accumulate in the blood and in muscle cells. A burning sensation in the muscle, shortness of breath and fatigue are all symptoms of lactic acid build up.

The AL System Will Work At Capacity For As Long As Two Minutes Resulting In Lactic Acid Build Up. 

The AL System Will Work At Capacity For As Long
As Two Minutes Resulting In Lactic Acid Build Up.

3. Aerobic Energy System

      The aerobic system is the most utilized of the three. It provides energy for low intensity activities that last anywhere from two minutes to a few hours. Unlike the other two systems, the aerobic system requires oxygen and takes much longer to overload. Sports and activities that use continuous sustained efforts such as long distance running.


In reality, most sports use a variety of energy systems, or at least the power (time to reach peak output) and the capacity (duration that peak output can be sustained) of the system.