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  • Writer's pictureTomas Wurst

How to improve sport specific performance. Part1: Understanding & training the 3 energy systems


To improve sport specific performance you need to understand and then train efficiently the 3 energy systems, as exercise physiology is underpinned by them.

When we exercise our body is constantly working to supply muscles with enough energy to keep going. The way energy is made available to muscles changes depending on the specific intensity and duration of exercise

Different sport situations have different energy demands. In some situations, energy must be supplied very quickly for the muscles to produce high-intensity results. In others, energy does not have to be provided at as high of a rate, but must be supplied over a longer period of time.

Overview of the Energy Systems

  • Adenosine tri-phosphate (ATP) is the only energy source for all bodily functions and activities (movements)

  • When ATP is used for energy production it must be replenished

  • The body can replenish (recreate) ATP aerobically or anaerobically

  • There is one Aerobic Energy System which requires oxygen to replenish ATP and two Anaerobic Energy Systems that can recreate ATP to produce energy (without the need of oxygen)

These are the 3 Energy Systems

  • ATP-PC System or Alactic System – ATP and creatine phosphate (CP) are present in very small amounts in the muscle cells. The system can supply energy very quickly because oxygen is not needed for the process. No lactic acid is produced in the process (Alactic)

  • Anaerobic Glycolysis or Lactic Acid System uses carbohydrates (glucose) stored in the muscles as Glycogen. Because no oxygen is required to re-synthesise ATP, energy is produced quickly. Also because no oxygen is used in the process lactic acid is produced as an end product.

  • Aerobic System – This system uses carbohydrates (glucose/glycogen) and fats to replenish ATP. Because oxygen is required for the process, energy production takes a little longer but can continue for a much longer duration. Because of the presence of oxygen, no lactic acid is produced.

Intensity, duration and fitness levels

The energy systems are all working at the same time to keep replenishing ATP (At no point will only one energy system will be used).

Yet, there is most commonly a predominant system.

The predominant energy system used during exercise will depend on the intensity and duration of the activity and the individual’s levels of fitness:

  • Intensity of exercise. (How hard you are working). The more intense the exercise the greater amount of (Anaerobic Energy) – Creatine phosphate and muscle glycogen will be used. Low to medium intensity exercise will use predominantly the aerobic system

  • Duration of exercise. (How long you are exercising). E.G. If the exercise is high intensity and lasts over 2 minutes then both CP and Muscle Glycogen will become depleted and need repaying. Intensity of exercise will drop as the aerobic system becomes more dominant.

  • Fitness level of the performer. Individual levels of both aerobic and anaerobic fitness will impact on the predominant energy system being used. A higher level of aerobic fitness will mean it will take a performer longer to reach the Anaerobic Threshold (The point at which the performer gets more energy from the anaerobic systems rather than aerobic). This is beneficial because when a performer begins to work anaerobically there is only a limited supply of energy available (PC and muscle glycogen - up to 2 minutes max). If the exercise continues to increase then the performer will run out of anaerobic energy and return to using aerobic whereby performance will then drop. This can be seen at the last few stages of the multi stage fitness test where the performer struggles to stay in time with the ‘beeps’ and eventually has to stop. The greater the anaerobic fitness the longer the performer can work in the anaerobic zone. In reality most people have anaerobic stores that last just over a minute. A trained performer can last up to 2 minutes, and also be able to ‘tolerate’ greater amounts of lactic acid in their muscles.

Sport specific simple examples and practical application

  • ATP-PC system is predominantly used during maximum intensity activities lasting no longer than 10 seconds such as weight lifting and power lifting, 100m (or less) sprint, etc.

  • Anaerobic Glycolysis system is predominantly used for high intensity activities lasting approximately 1 minute such as surfing, 400m sprint, most gymnastics types, diving, etc

  • Aerobic system is predominantly used during medium to low intensity activity such as marathons, over 1km run, skating, cross-country skiing, etc

  • The predominant energy system being used at rest is the aerobic system.

Remember that the energy systems are all working at the same time to keep replenishing ATP (At no point will only one energy system will be used). The energy continuum below illustrate well the percentage of the energy systems use during some sport:

The above are general guileless which surely will help you to choose the correct training programs and platforms for your sport specific requirements. Nonetheless, if you are serious at becoming a better athlete, I strongly recommend to seek a professional sport specific fitness coach. We certainly, CAN help: Contact us >>

Tomás Agustin Würst, Fitness Trainer, Yoga Teacher and Manager Director at Workout Australia. Have a question? Get in contact:

The information contained on the on Workout Australia website, Articles and so on, is not intended to be a professional medical advice, diagnosis or treatment in any manner.

Always seek the advice of your physician or other qualified health provider with any questions you may have regarding any medical condition.


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